Unable to add groups to instances

[Crossedfall]

Whenever a group (with members) is added to an instance, it adds the first member of the group instead.

Reproduction steps:

1. Create a group
2. Add members to the group
3. Attempt to add it to an active instance

Expected: The group will be added to the instance and you can set perms Actual: A user is added instead of the group

[Crossedfall]

Note: Adding a group without members first, setting the perms, and then adding a member to the group will remove the group from the instance and add the member instead.