routing upload requests

[azeem ahmad]

hi list
i am running a small network of about 80 clients which access internet 
through my squid server.
squid is connected to internet with two different upstream peers. i.e.
cache_peer peer1
cache_peer peer2
i want to configure my server in such a way that if any user is uploading a 
file heavier than 2Mb than upload must go vi peer2 route instead of normal 
peer1 route
is there any way to do this

Regards
Azeem