Priority via multiple Interfaces including VLANs

[SteamboatWillie]

Hello,

I use pfsense 2.0.2 (update not done till now because there was no free maintenance window in my company).

I have

• 1 LAN Interface
• 3 WAN Interfaces
• 1 OPT Interface with ist connected to my Wifi Network
• 3 VLANs assigned to OPT Interface as 3 Wifi Networks are split via different VLANs - we call it VLAN1, VLAN2, VLAN3
  All VLANs access then Internet via WAN1 which is the default route
• 1 OpenVPN Server running

What I want is, when someone from VLAN3 access the Internet, the connection should have a lower priority than anything else what passes WAN1.
If no one else access the Internet via WAN1, users from VLAN3 can have the full bandwidth of WAN1, but I do not want, the users from VLAN3 are slowing down the Internetaccess for the other Networks.

Can this be done via pfsense Traffic Shaping?
And when it can be done, could someone give me an advice?

A question similar to this has been asked a 2 years ago but seems to be intented for pfsense 1.X
http://forum.pfsense.org/index.php?topic=39894.0

Is priority summed up over multiple Interfaces?

Do I need to set priority queues for traffic on every network on my interfaces?

Should I use the Multi LAN/WAN Wizzard and then extend these queues?

Where do I append these to which firewall rules?

Any advice would be nice!