Send specific traffic through VPN based on the domain
You're looking for static routes and the 'route' command.  'man route' from the shell for full info, but something like route -nv add -net 66.22.138 -interface tun0 (or whatever your VPN interface is) should route traffic bound for hulu.com over the VPN.

You'll probably want to establish a default gateway so that you are assured of routing your traffic correctly.

route add default 192.168.1.1 would add a static route for your router.  Replace 192.168.1.1 with the actual IP address.

Note that these settings will not survive a reboot.  If they work for you, you'll want to put them in a launch agent file.