question

Yes you can. Here is a basic example:

setvarexample.fsm

In the model I simply added some code in the processor in the OnEntry trigger:

if (getitemtype(item)==2)  {
	setvarnum(current,"nrofprocessoperators",2);
}
else  {
	setvarnum(current,"nrofprocessoperators",1);
}

Simply. if the item is itemtype 2 it requires 2 operators for processing. Otherwise just 1.