[SG2]: GSM/P Question

Played first game of SG2 and enjoyed it but we had a situation where a
GMS/P was fired at a unit. Followed the rules on page 40 for GMS die
rolls and got a 'fully effective' result. However the rules say that the
number of potential hits are determined by dividing the total firer dice
by the range dice - GMS's don't have a range dice! How do I determine
the number of hits?