Vlan and switch

Hi, i'm wondering if this is possible.

I have a mpls connecting to remote offices, isp handles traffic over vlan 100, so at the time i have my 4 servers and one fortigate subinterface  on vlan 100.

Also i have a cisco 2960 switch as a core switch connecting servers, fortigate and switches.

This switch handles 2 port-channels connecting the fortigate with a couple vlan's.

So i'm wondering if is possible to have 4 ports of my fortigate as vlan access on vlan 100 and handle incoming tagged traffic over port-channel.

Thanks.