District email groups are powered by Google Groups and that service maintains a record of everyone's group membership.
1. Load your groups page (sign in to your district email account if you haven't already)
2. Once your groups page loads, you'll be presented with the list of your email groups:
If you want to see other members of one of your groups, click on the group name, then click the members link
The members list should load, showing you all the current group members:
That's it! If you're not in a group that you should be, check out this article for more info.