I think you should talk to your T about it and get her spin on it. I don't think you should go to the other counselor and hide it from your T. That could really make you feel guilty!

Some therapists don't like their clients to see anyone else--no exceptions. I have had some overlap in therapists and did not find it a problem. But they each had their defined role (in my mind, at least). I have my regular T, with whom I have a longstanding relationship. I had several sessions with a therapist who specializes in children going through divorce. The focus was on my kids, but we talked about other stuff sometimes too. I only had about 3 (multi-hour) sessions with her. I also had a family therapist who worked with me and my daughter. We saw him for about 9 months while I was seeing my regular T too. I had a couple of sessions with him alone. I have a PNP whom I see monthly, and she is also a licensed therapist. Sometimes I see her briefly for meds, other times, we have a longer session to talk, and it counts as therapy. I get different things from all these people. I have found myself talking to them about different topics. Especially to my PNP, who is female, I sometimes find myself getting onto other topics than I have discussed with my T, and I think it may be because she is female. Kind of woman-to-woman stuff. I like having both a male and female in a helping role in my life. I really like my PNP, but I am not strongly attached to her. I felt there were times when I was attaching a bit to the family therapist, but having another person in the room during therapy impedes that process. My own philosophy is that if you can keep the different Ts straight in your head as to what they are helping you with, then it can be really useful. Where it might be a problem is if you wanted to work on the exact same issue with the two therapists, and they had different approaches that were at cross purposes with one another. If my T had a problem with this, I bet he would have good reasons, and I would most likely listen to him. He is the one who has referred me to all of these people, so I know it is OK with him, and sometimes we have even briefly discussed something going on in therapy with one of the other Ts.

That sounds like a really good reason to establish contact with the counselor. Be sure to mention this to your T. It could be you would only need a couple of sessions with the counselor in order to be referred to the group.