Only direct certain URL requests to proxy using SonicWall

Question

I'm wondering if there's a way to route only certain URL requests to a proxy. It would be fairly simple using IPtables, but I'm using a SonicWall TZ100 (using SonicOS enhanced 5.5.2.1). I'd like to send all traffic to the default gateway (which is what I'm doing at the moment), but I have 2 URLs that I'd like to direct to a proxy.