in case anybody's wondering how to enable transferring units from nation to nation, one goes about it by altering "graft" and modifying the "tribe_mask":
the "tribe_mask" from left to right:
mongol
korean
japanese
chinese
russian
german
british
french
spanish
turkish
egyptian
roman
greek
nubian
bantu
incan
mayan
aztec
the "tribe_mask" from left to right:
mongol
korean
japanese
chinese
russian
german
british
french
spanish
turkish
egyptian
roman
greek
nubian
bantu
incan
mayan
aztec