Since the guidelines ask that OT posts be kept to a minimum, could this please be addressed in IM?
To IM any cousin:
If you know their exact username (which can differ from the display name), access the feature under the forum logo (the underlined part of Hey, _____, you have __ messages, __ are new.), then click new msg.
Or click the green page in any of their posts.
Or click on the cousin's [display] name in any of their posts, then at the bottom of their profile select Send this member a private message.
Thanks!