Shield Wall

Prerequisite(s): Shield Focus
Benefit(s): While you are adjacent to an ally that possesses this feat and is wielding a shield, you grant them a +[x] circumstance bonus to AC.
[x] is equal to +1 while you are wielding a light shield
[x] is equal to +2 while you are wielding a heavy shield
[x] is equal to +4 while you are wielding a tower shield