It may take some creative solutions. We have groups as well, and I can communicate with very few of them directly. However, there's one person in our system who can communicate with most of the rest of the system, so a lot of the communication has to go through her. It may not be possible to get everyone all together right from the start--you might have to facilitate smaller conversations/meetings with each of the groups, possibly with the assistance of someone inside who's able to communicate.

It's okay not to have it all figured out just yet. I still don't have a lot of it figured out, and I was diagnosed something like five years ago. It takes time and patience--you're building relationships just like you would with outside people. Not everyone's going to trust each other and work well together right at first, but it's something you can work toward.