Policy based routing on web address

[nortis]

Hi,

I am busy setting up a pfsense firewall. We have two wan's and I would like to route traffic based on web address. For example we would like to route all facebook, youtube… stuff through the one wan and all other traffic through both.
Is this possible with the pfsense 1.2.3 at all? Alternately is there a way to throttle specific sites?