po-devs/pokemon-online — pull request #1321 by VeteranPadgett (2014-12-01 06:42:06+00:00)
Title: You can define a tier to not allow Pokemon obtained in earlier games

You can set the minGen in VGC 2014 to "6" to enforce pre-pokebank. Only thing this matters for right now, but VGC '15 will probably have the same rule.