So I have a DrumRack with 8 InstrumentRacks each nesting a Sampler. Each Sampler is mapped identically to the Macros in the hosting InstrumentRack. Sampler 1 is for kicks, 2 is for Snares and so on.
If I right click on a parameter in a Sampler OR on a Macro, I get an option saying "Copy Values to Siblings (7)" If I choose it it will copy that value to all other identical values.