Group workings can take many shapes and forms; they can be long term deals with folks you know really well, one-off workings done at the spur of the moment, or anywhere in-between. They can be done as part of a coven, magical order, brotherhood, sisterhood, etc. and often have specific rules of engagement attached per the individual(s) directing the group in question.
For as common as it is, I find it to be interesting that few ever really seem to discuss the specifics regarding the personal effects of engaging in such practices. There seems to be a widespread assumption that its no different than solitary workings, and that's about as much discussion as I ever see on the subject. That being the case, it sees pertinent to discuss some of my own observations here; as always, feel free to disagree.
Before I get started on the specifics, I should note that my experiences and observations come from the vantage point of someone who has been largely solitary for the better part of his life. I don't gravitate towards working with(in) large groups of people, as it really doesn't fit my style. The way I see it is that if one is subject to the views of another person, he or she will go no further than the teacher. As a result, I've always been the sort to listen closely to what someone has to say, and then question the everliving crap out of it. I like to think that its made me a fairly effective sorcerer, but its the very reason that I've never been a part of one of the more well-known magical orders that seem to crop up frequently in these sorcerous circles.
My experiences with group work have been, largely, limited to workings and pursuits with close friends, involvement in a uniquely screwed up cult, short-lived planetary magical groups, and a heathen kindred that I wrote a few rituals for (and participated in several written by others). That's about it, as I find myself dubious of the intentions of others, as well as generally unwilling to trust in their skills. I am a bit of a control freak, and I know better than to allow myself to get roped into working in ways that are going to come around and bite me in the arse later.
Trouble is, that mindset generally sets you apart from the folks you might gravitate towards. Greater knowledge really does leave you out on an island, so there are times where you have to weigh the risks of working with folks who may not know what they are doing and, as a result, might cause you some trouble in the future.
That is the purpose of this post, as I find folks are generally unaware of how the actions of others they are tied to can affect them. This is doubly true when dealing with magic.
When things go wrong and you've been a part of a major group working, even if it is something as simple as doing healing work for a person, you are directly responsible for the things that happen as a result. This is for both positive and negative actions, and all of these actions are tied to you, affecting how you are going to interact with society, and with these people, in the future.
Karma isn't some abstract thing that mandates that every action's effects will come around threefold, but it is instead directly related to the debts created by your actions. Everything you do has ripples that expand outwards, and sometimes the momentum created by those actions (or inactions) cause unintended effects a long time down the road, catching you completely off guard.
When this happens, its important to take responsibility for the things you caused and then deal with the situation in an appropriate and responsible way. Sometimes, the way you do this is going out and cutting the ties.
As an example of one such occurrence in my life, well over a year and a half ago, when I was still a part of a heathen kindred in AZ, I led a blot (Norse rite) on Freyfaxi for the God Freyr. I remember knowing, for some reason, that if two of my friends participated in the rite they'd be getting pregnant with their third child. I even warned them as such, but still proceeded with the rite like any good heathen'd do. Lo and behold, these two folks got pregnant, just as I predicted, they had their child and suffered all of the associated boons and ills. I even babysat the little one when the mom had a fever, after I took her and her husband to the hospital. I was at the little guy's funeral after he had died of crib death. I am, as a result, directly or indirectly responsible for the changes he caused in the lives of his parents. I am responsible, as a result, for the effects the birth, care of, and death of the child had on my ex-wife and everyone else we knew, all because I lead a blot.
As a result, my orlog and wyrd did get all sorts of dorked up, just from this singular event....never mind all of the actions I took as a result of leading the blot. I had to make a point of going back and cutting the ties created and tying off the threads that would lead me down roads I don't want to go. I had to separate myself from the threads of the aforementioned folks, as I no longer wished to be tied to them and their actions, and even that action has had consequences of its own.
Such are the consequences of any group working, and this is only one such example. I hope it serves to illustrate what can happen when you work and bond with others, and with any luck, this'll give you cause to think about how you proceed. Very little in this world is trivial, and there are times where even helpful actions that bring you a lot of joy can bring you a great deal of sorrow down the line.
When your actions have unintended consequences, you will need to wisely take steps to separate yourself from the situation and/or work to remedy it as directed by your divinatory exercises. When in doubt, seek out someone who can read the threads of fate and act accordingly.
Just something to think on.