firewall rules - allow/block networks

hi all,

i know in pfsense and TMG you can add static routes for different networks to your VLAN switch and from your vlan switch add a static route to your router then in the "firewall rules" you can create allow/block rules so the LAN networks cant gain access to the WAN or certain LAN networks cant talk to other LAN networks

i was wondering as im going to be using just a basic home router flashed with DD-WRT or i was looking into buying this billion 7800n, can i add LAN firewall rules so i can block/allow certain networks like above

rob