Limitation of Unlimited HIt for squid Using Simple queue

Dear colleagues,
I have a problem with my network, hope someone can help me with it.
My clients are pppoe and i’m using a squid server, all works fine and my clients can downoad at full speed from the squid cache Server.

the problem is with some wireless Links that it can not handle a lot of traffic passing through it when a client is downloading a movie or something from the Squid, is there any way we can limit the Hit of the external squid box for each client (let’s say 768k) with simple queue for each client?

Waiting for your reply,
Regards