My bad, Moov physics does not have a Strand Groups field just yet.
Roots Channels are designed to isolate some parameters to painted strands or strand vertices. For example, if you select some strands, create a strand channel and paint them white, the parameter where you apply this channel will only affect the white guides. Find more about strand channels here: https://ephere.com/plugins/autodesk/max/ornatrix/docs/6/Guide_Channels.html
In Moov Physics you can mask out a few parameters using strand channels, but you cannot mask out the whole modifier. You can paint a strand channel to control the Mass, Stiffness, Force fields, etc.
Jeordanis Figuereo (Product Designer. EPHERE Inc.)