Hi
I have been through this. I have a unit attached to main house with its own entrance. Thats what I claim under rent a room (seperate but attached unit) My tenants are not tenants but licencees and they have a licence not a tenancy. RTB were all over the shop on this - they have not got a clue - told me to register, then deregister, then refunded me.... From what you say I see no problem, if they share with you or are in separate but attached its still rent a room. It cant be a stand alone seperate building. How you break up the shared space is up to you - it can be shared kitchen, bathroom, utility etc. Thats written into the licence which you draw up yourself.