subject already says it all
I would suggest there to be a portal room aswell as an arrival pad chamber. Most communities have no exit, you can only port in and hope to be bound elsewhere or have a long journey back to where you came from, which renders the chamber with the binding gem almost without use. Give those who have lairs in the far away outskirts a far chance to travel, they would love it
Because those chambers are something special because of superior usefullnes, it might be cool to make them harder to build. Tiniest version to be T5 or T4 for excample.