You can set up a special world that will allow you to store all the TARDISes in it and still be able to grow rooms. The world must be called TARDIS_TimeVortex and must use TARDISChunkGenerator or be a FLAT world type.
To set this up:
/mv create TARDIS_TimeVortex normal -g TARDISChunkGenerator
/mw create TARDIS_TimeVortex plugin:TARDISChunkGenerator
/tardisadmin default_world true /tardisadmin default_world_name TARDIS_TimeVortex /tardisadmin include_default_world false /tardisadmin create_worlds false
As of TARDIS v2.7-beta-1 the plugin now uses a system called T.I.P.S (TARDIS Interior Positioning System). This system places new TARDISes in a specific ‘plot’ in the TARDIS_TimeVortex World. This means that TARDISes will no longer overlap other TARDISes if they are created close together in the overworld.
If you are using a pre-TARDIS 2.7 version, you will have to educate your players to create their TARDIS home locations far apart as their position in the TimeVortex relates to the position they were created in the server world.