[arch-releng] Building both 32&64 with custom packages

I have got my build script working building both i686 and x86_64 without problem. Have custompkg repo set in pacman.conf for dmenu-xft [from AUR]. Not sure if pacman will work if I set both custom repos... only other way I can think of is sed pacman.conf [for i686 or x86_64]. Never tried using a custom repo that had both 32&64 packages anyone got any better ideas?