ForScore provides the facility to set up a "match within a match", where SIDE shooters compete against each other only on stages which have been designated for them.  That way, for example, someone can shoot 3 SIDE stages in a match that is otherwise set up for 6 stages and not have his entry show as incomplete.

Information specific to registering shooters in SIDE division is in the registration section of the documentation.

 

 

Just define which stages will be used by SIDE shooters.  If any SIDE stage has more than one string, use the spin boxes to indicate the number of strings.

(NOTE:  SIDE stage 1 need not be held on the same physical range bay you're using for the regular match's stage 1...  I usually start numbering SIDE stages consecutively at 1, because I think they're easier to read on the results printouts that way.)