Na physical punishment won't adjust behaviour in any way and moreover ends up being a badge of excellence for some kids.
The only way is to segregate the disruptive kids. Move them to another part of the room at first, then into their own room. Now there will be a lot of boooos thrown at me I'm sure but fuck it if parents can't teach any discipline then their asshole kids should not be allowed to negatively impact the education of other kids.
Social isolation has a huge effect at any age and there is actually a positive aspect to it:
http://www.huffingtonpost.com/scott-...?utm_hp_ref=tw
