Thanks for being sensitive to the need for the safety of vulnerable road users. My personal view is that we should all see ourselves as partners on the road and make every attempt to help each other out. If cycling, this means understanding the negative effect of long lines of riders on motorists. The group rides that I participate in have a standing rule that riders should avoid bunching into groups of 10 or more. Sometimes this is hard to avoid, for instance when going up a long hill.

I'm not sure what you can do about it, though, other than trying to connect with some of your local cycling groups to discuss. Perhaps a sign on the side of the road that has a polite message to cyclists asking them help out the motorists.