Well I've just checked the official "Club Rides Rule Book" version 26.3 dated 4-20-20, current revision.
It clearly states the first person to complain MUST immediately make it clear to those that are violating pace line pulls doctrine that they have to follow said rules or be constantly reminded they are in violation of said rules until they conform.
It is now your duty as chief complainer to make it known to the miscreants.
Penalties included constant complaints during the ride and a lowering of air pressure in their tires until they conform.

IMO if they are pulling at the pace I want at that time I'm more than happy to sit on their wheel and enjoy the draft. If I want more work load I'll pull out of the line and do the work until I've completed my effort then slip back into their draft.
The only way to really combat this is to state the rides goals before it starts. If someone decides to do what they want the group can move aside and let them ride alone even if it means slowing a bit until a large gap occurs then resume your ride. If they complain simply remind them of the rides states goals.
The last thing I want is to be in a group ride and have to listen to complainers on either side of the line. I'll make it clear I'm there to have fun and ride with like minded people not a "***** fest" and will ride away on my own.