You may have already hammered this out with your group but I've found that 'safe sex' and 'barriers' can mean very different things to folks. For example, will the group use barriers for oral sex? Every time or sometimes? Or only when having PIV? What about using gloves? I suggest having lots of rather detailed, explicit conversations about what safe sex and barriers are for everyone, and hopefully get an agreement that everyone understands and accepts.
I would also make sure that everyone knows the STI's a particular clinic tests for. Not all clinics test for everything all the time. Some don't test for herpes or they may not test for more obscure STIs.