mob template? as applied to the denizens of each city?
seems social engineering would be a reasonable tactical approach.
you could always write a ginormous backstory, larger than the dm is likely to read, and bury in there that you came from another location where the psionics are different option is in effect with relation to all the locales you will be fighting them in. ^^
speaking of psionics, metafaculty will get past all of their defenses, damp power has already been mentioned, protection from spells, many other options.