multiple VLANS for one virtual Interface

Hello,

After days of searching I have no more ideas how to setup the following.
I have several VM's to evaluate new software before going to production system.
I am changing from ESXi to Proxmox and have some Problem with VLAN Setup of VM's.
There are 5 VM's created Windows2008, Windows7, Windows2003, WindowsXP and Endian Firewall.
The Windows2008 and Windows7 should communicate to each other but not to the Win2003 and XP.
The Win2003 and WinXP should also communicate but should not connected to the Win2008 and Win7.
I have done this by creating a new Bridge vmbr1 with no IP and add VLAN Tag 1 to the virtual Interfaces of Win2008 and Win7.
VLAN Tag 2 is assigned to the virtual Interface on the Win2003 and WinXP Guest.
So far everything is working fine.
The Firewall VM have 2 virtual NIC's one (red) to vmbr0 (connected to the network outside) and the other (green) connected to vmbr1 (to the VM's).
How I can setup the green virtual interface of the firewall to connect to VLAN 1 and VLAN 2 so that booth VLAN's can access the firewall.

Hope somebody have an idea.

best regards
Thomas