Work groups used to be my biggest struggle as well. Feeling excluded from the conversation and the jokes. Often being too scared to say anything because I didn't want to "ruin the flow" of the conversation. Learning to change my relationship with my stutter and completely reinventing my self esteem was what allowed me to now be the leader of most group conversations, not being controlled by the stutter at all. I could tell you everything I did but it would take a year to type it all out. Lets start with what you are doing right now to work on this. Whats your action plan to get over this ?