VPN for VLAN Only?

I am running a Asus RT-AC66U with Tomato Firmware 1.28.0000 MIPSR2-3.4-138 K26AC USB AIO-64K.

I have been trying to get a VPN setup for one VLAN, but can't seem to figure it out; so, is even possible to establish a VPN connection for a single VLAN only?

I tried posting in the networking section, but it doesn't seem like many people venture to that forum anymore.

http://www.linksysinfo.org/index.php?threads/vpn-setup-issues-with-vlan-bridge-on-tomato.73265/