I would find out a few things about this group: is it therapy or support? The two are considerably different. Is it professionally or self moderated? Again, the two are different. If possible (my own choice speaking here) is that you find a 'self moderated support group'. The advantage of this is that being a support group it is about caring and sharing. The advantage to something being self moderated is that there is some freedom afforded by the fact a professional is not present (many get hung up by the idea they might be judged if they speak in front of a professional.

Find out the contact person(s) and maybe give them a call. I think you'd glean a lot from them in terms of whether this group is right for you. Also, many groups accept the addition of a support person when a new person comes to a meeting.

Finally, don't go in to attending a meeting with the thought by going you are making a commitment. Make your own conclusions after dropping in and paying them a visit.