Yes, we do have a lot of different groups, and it can get confusing. However they all signify that group's status. Many have both size, geographic and other requirements to be fulfilled before a group can attain that status.
All local groups belong to a Kingdom.
We belong to Trimaris. Principalities require a minimum of 100 paid members, a full set of Principality Officers who report to their Kingdom's Officers, and a Prince and Princess. Again the possible sizes are similar to Kingdoms. Smaller local groups can belong to both a Principality and a Kingdom. This is a collection of local groups used to aid in the administration of the area.