There was one lowend groupette (shifter + RD) that only worked with each other it was like A 4030 or something. otherwise it is pretty much like shimano SIS if the shifter is 6spd and FW 6 spd the system should work regardless of RD.
I actually ran a set of 7spd suntour barcons and FW with a 600 RD for a few years on my commuter, it worked OK.
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk