So we add another sanctum you can join later
so it looks more like a pub/club has message boards
member list
-could be linked to guild doesn’t have to
besides mesageboard and maybe mailboxes its does nothing more then what a solo sanctum does
ow maybe replace the dude with this band boundless style
Or maybe build your own Sanctum? 
Private Space Lots would make an excellent precursor to owning your own planet… only sad part to private planets and private space is that city prestige increase may slow to a trickle 
Guild portals to a private guild lot…? And the destination plot of the green guild portal gets the private guild lot’s prestige?