I've found that talking to Alpha-males of the group before hand and asking them, "This is a no-drop ride, right?" helps alot. It puts it in their minds before they even start that they may need to slow down or wait for you. Around here they usually just wait at an intersection so you know which way to go. Or sometimes they'll have someone come back and ride with you. I always imagine them drawing straws to see who gets stuck with the slow girl.