Spaces are a superset of tagging. Just create a space (tag) and the rooms that you want to tag to it. If you want it to be just for you keep the space invite-on

Spaces are a superset of tagging. Just create a space (tag) and the rooms that you want to tag to it. If you want it to be just for you keep the space invite-only, if you want to share your "tag" you can.