Router/bridge/vlan

Ok so here is what I am trying to figure out. I have two tags 10 and 20 coming into my 450G ports 2-5 are currently bridged and each tag goes to a separate hotspot on the 450G. All is well.

Now I want to do the following.
Still have tag10 traffic go to my hotspot say ports 2-4 bridged. Then i want tag 20 traffic to go to port 5 no longer in the bridge and pull a dhcp from a dink plugged into port 5. is this possible or do i need to assign each port to the hotspot? Then that would fail because there not tagged. Looking for any ideas?

I know I can just put in a switch before the 450 and send tag 10 to the 450 and tag 20 to the dlink but I really want to try and elminate a switch to just do that and have the 450G do it.