Knockback When Grabbed

[Koshka]

Last game, one character grabbed the legs of a minor bad guy, then another character hit the same bad guy and did knockback. The GM thought he remembered a rule about grabbed characters taking KB, but none of us could find anything in the books. The impromptu ruling was half KB distance and the grab was broken, but is there something official we missed?

[Steve Long]

There's something in the Rules FAQ about this; that may be what you're remembering.