It seems like a 70s or very late 60s movie... towards the end of which, a whole bunch of men in overalls come out of an elevator in an office building and kill a whole bunch of men in suits... previous to that, there's a whole bunch of men holed up in some stronghold ranch out in the desert somewhere... I don't remember anything else about it... not even who acted in it, although I'm sure some heavy names are in it... I believe it's either an American or Canadian movie... most likely, American...