it doesn't bother me if one or two people have to leave and rejoin their group, as long as they're polite about it. my mom has a medical condition that causes sudden urges, so sometimes when she has to go, SHE HAS TO GO. i'm pregnant and even though i visit the restrooms often, sometimes it will hit me all of a sudden at an inconvenient time (and sometimes all the junk i eat in the parks can do a number on my stomach, unfortunately). i know that there are certain points in the queue that make it difficult to rejoin, so if/when one of us has to leave the line, we usually know the easy entry points and just wait for each other there instead of having to squeeze through everyone else.