It should work, as long as you use a block size for your program (as specified in the IDE settings, not using Pd's [block~]) that is equal to the hop parameter of sigmund~ (defaults is 512). This is the sort of processing that would really benefit from a separate core, so I am not sure how much CPU time will be left after using it on one string. I doubt running 6 parallel instances is at all feasible on Bela, although you could use a gate to route the incoming signal from the active string(s) through one of a handful of instance, or alternatively [switch~]ing each instance on/off if there is no signal coming through that string.
