When they eventually have the faction vendors represented at Whitesprings (not sure if this is tomorrow or coming with "player vending" next month), I believe this will happen on its own. Whitesprings is already a location where some number of players are hanging out, and if you put all the vendors there, there will be little reason to fast travel anywhere else.
I'm interested to see the players gather together when the faction vendors arrive at the Whitesprings. I do feel like this will naturally turn into a player hub but I'll mention this overall idea to the team. :)