Network Hardware Questions

I know this is a unusual question but here goes.

At my office we have multiple sub domains that point to static ip’s which are setup in our pix and the forward to the web-servers on the internal LAN.

I want to be able to have multiple sub domains point to the same static ip and then the firewall see that the request is for x.y.com and forward to the correct web-server and port. The only way I think this is possible is if the firewall has internal dns table to handle this.

Does anyone know of a firewall that can do this?