Physical ports as part of another network

Hello everyone, I have a simple question, or not so simple? I have an 802.3ad aggregate interface consisting of wan1 and wan2. On this I have configured several different VLANs interfaces. This interface is connected to an Aruba stack that concentrates all my links tagging them and connecting it to my FortiGate through a LACP trunk. My doubt arises from the need to use some of the ports of the FortiGate, for example lan1-lan4, to be part of one of the VLAN networks, let's say VLAN 10, with IP 192.168.22.1/24. What do you recommend is the best way to achieve this?

I understand that software-switch and vlan-switch could work, but I don't know which would be the best option in this case.

I've a FortiGate 101E and FortiOS 6.4.5 build1828 

Thank you very much in advance for the help. Best regards,

Gabriel.