VLAN for Apple Airport in CRS Switch and RB Router?

We are a church and I would like to setup private and public WiFi. We have a Comcast Business Internet account with a static IP. We have a MikroTik RB1100AHx2 router and a CRS125-24G-1S-IN switch.

Attached to the switch are, two Apple Airport Extreme WiFi Access Points acting as a bridge and allow full network connectivity. I’d like to set up a third Airport AP with router functions so we can share our Internet but not allow access to our private network. I cannot use the built-in Guest mode on the Airport as it needs to be the first router after the Internet.

Is there a way to configure a VLAN on that port on the CRS Switch (RouterOS) so it will only route Internet traffic over that port? The Airport does NOT support VLAN so I would have to do this at the switch level.

Thanks!

FYI. I have since found http://forum.mikrotik.com/t/vlan-1003-for-airport-extreme/90963/1 and looking to see if that answers my question.