Replacing ISa 2006 with Squid/Pfsense???

[Supermule]

I am looking into replacing ISA2006 with Squid and Pfsense.

Currently I am running PFsense as frontend FW, with ISA2006 as backend. ISA is handling multiple webservers/mail and SQL.

I need to publish the Mail and SQL servers and traffic needs to be redirected based on header information to multiple webservers.

Can Squid/Pfsense handle this kind of setup and how should I begin to replace the ISA2006?

All helt would be very much appreciated. I am new to Squid(Microsoft guy looking to get som pingvinblood into his vains) and therefore pls start with absolute basics, so I have a clue of what the options and possibilties are :)