Its the .3DS hierarchy problem again. If EntityAlpha had a 'recursive' flag it'd be easy. Until then, something like this should work (haven't had time to test):
Function RecursiveEntityAlpha(entity%,alpha#) For N = 1 To CountChildren(entity) If EntityClass$(GetChild(entity,N)) = "mesh" EntityAlpha GetChild(entity,N),alpha EndIf If CountChildren(GetChild(entity,N)) > 0 RecursiveEntityAlpha(GetChild(entity,N),alpha) EndIf Next End Function