Script to equip an associated item

[SAC]

I would like to write a script which identifies the outfit an NPC is wearing, and equips an alternate, non-replacer (!) version.

 

Something like "if NPC is wearing the vanilla undershirt and jeans, then unequip it, and equip my own version of (non-replacer) undershirt and jeans"

 

Yes, I can hardcode the associations, exactly as written above, using the nominal base ids of the outfits, but I would prefer something more elegant than that. Something like a relationship / lookup table, if that concept even exists in papyrus.