Restricting vlan to one or more wan ports?

I have configured a vlan for a group of lan clients.
I would like to restrict this vlan to a single wan port for both inbound and outbound internet traffic.
I have set an outbound policy rule to restrict this vlan to a specific wan port, and specified a vlan port in port settings, but there is persistent inbound traffic on other wan ports especially with torrents.
I would also want to allow the regular non-vlan clients access to the same wan port in load balance mode.
Any advice would be appreciated.

Controlling the outbound traffic is no problem via the custom outbound rules, but incoming traffic is completely different. This is controlled by Inbound Access settings.
If you are trying to restrict inbound traffic I recommend to do this via the Firewall. First change your default inbound rule to Deny All and then start creating Allow rules for the legitimate traffic.