Can i use a guest VM to trunk/connect ESXi vswitch port group vlans?

Hi everyone,

At the moment i have:

4 x Windows 2003 guest vm's each on their own subnet.
4 x port groups on vswitch0 each assigned a unique VLAN ID and then one of the above guest VM's allocated to each port group.

The idea is to have each guest VM in it's own VLAN, which i think the above achieves using Virtual Switch Tagging.

My question is do i really need a physical switch to perform the trunking or is it possible for me to install a linux vm or a pfense vm and have it be aware of the four vlan port groups and then perform the routing between the four windows vm subnets?

I know pfsense supports 802.1q vlans but what i get stuck at is understanding how the pfsense guest VM on the same ESXi host as the windows vm's will see traffic from all 4 of the vlan port groups.

I don't know if the default 'VM Network' port group which has no VLAN ID automatically trunks with all it's sub port groups so any VM in there will see all VLANS ?

Apologies if this doesn't make a whole lot of sense. If anyone can offer some pointers id appreciate it. I'd rather not have to go out and buy a switch to trunk four VM's if possible.

Many thanks
Scott