Well, there's good news and bad news.

First the bad news:
"Messages posted on Social Groups are subject to the same rules as posts on the forums. We expect that members of a social group will use the PM and e-mail systems to contact and dialog with each other concerning religious, political, or weapon discussions. Public messages regarding Social Groups posted on any section of the XMTS Forum will be subject to moderation and must meet the requirements of the Rules."

Just because the discussion is within a social group forum the overarching XMTS rulebook is not thrown out. There can be no explicit discussion, and no photographs, of modern, non-Highland weapons. Period.

Now the good news:
A group such as the one you propose can be formed for the purpose of facilitating contact between like-minded members. This is what the whole social group feature is intended for. You can do an awful lot with this group and still remain within the rules.

Here are some sample discussions that would be no problem:
-- kilts in tree stands...bad idea?
-- kilted fly fishing in Maine
-- what's your favorite hunting boot?
-- post your favorite venison sausage recipe
-- Who wants to go on a stag hunt with Jock Scot?

Here are some sample discussions that would not fly:
-- dacron or fastflight strings on your recurve bow?
-- which ammo for hunting coyotes?
-- shotgun or handgun for home defense?
-- photos from a recent 3D archery tournament

(sorry for the obvious North American slant...)

If you wanted to discuss strings, ammo, arrows, shotguns, or other forbidden areas, you'd have the option of PM or email, and forming the group allows you to target the messages to those who would be interested. As long as weapons are not specifically discussed or illustrated, the discussion would probably be valid. A post stating "Owners of Colt 1911's, please PM me" would be OK as long as follow-up posts did not launch into a discussion of that particular weapon.

Interestingly, there is no such prohibition on fishing equipment, despite the fact that a tuna flopping on the deck is probably just as miserable as a duck on the wrong end of a load of #4 shot.