An archetype with the Auto-Multibrush property is replaced with the multibrush specified in the property when placed in the world. The multibrushes (saved by the save_group command) must be saved in the Thief folder, with the .vbr extension.

So, instead of using the load_group command, which causes the multibrush to appear in a seeminly random location (actually, the centre of the screen, but never mind), you can use this to place multibrushes in a more orderly fasion. Remember to grid-snap brushes afterwards!

Property Name: AutoVBR