provide ability to turn off full-sync of groups during pspng incremental

provide a switch to turn off fullsync within the PSPNG incremental consumer.   i have several groups of roughly the same size (460k sourced from elsewhere) and when pspng thinks something is wrong (which is almost always) a fullsync takes about 45m so the incremental comes to a screeching halt.  I run full-syncs every night - they take about 50m.  The idea is to let every other aspect of pspng continue but when a fullsync is sparked within the incremental (i am hoping we can discern this) (gettes)