maybe they're talking about kilometers? then it makes sense
If there's an agreement to not drop folks, they need to stand by their agreement. If they always drop you, you do need to find someone else to ride with. I realize that in most areas, you don't have that much choice. There are some guys I ride with who wait for the slower riders... but then what are the goals? are you training for racing, or is this their idea of a pleasurable ride?