Here's my take as the PUS with very little brain: If the minimum # of pups is too much, you should first modify the type of pup for lower intensity. If that isn't enough, just tell the PUS (me) to put you in the next group down (fer instance, move from group 2 to group 1). If group 1 is too intense, keep modifying to decrease intensity - like using a bench, a higher bench, a physio ball, a wall, etc. By modification of the pup and the group, we should be able to follow the 6-week program as a group. Otherwise, the PUS and her spreadsheet will disintegrate before your eyes.
As the KISS-method PUS, this is my recommendation.
However, this should be approved by the PUC and PUO.