You could consider rolling all the associated forms into one and simply hiding those that are not needed
until a relevant selection is made - then use the setfocus event (or similar) to take you there.
I dont know of any way to import an entire form into another dynamically... but i could be wrong
Having form open other things locally gets tricky becuase acrobat/reader is quite touchy about security functions also -
sorry cant be more helpful - good luck