Fortimail in hybrid environment

Hello Friends

We are evaluating fortmail on cloud in server mode. Initial config is done and mail flow is working fine.My query is regarding using fortmail in hybrid environment. 

There are two scenario  

scenario1

Domain xyx.com 200 users are on gmail and 500 users are on fortimail. The MX will be pointed to gmail.

scenario2

Domain xyx.com 200 users are on gmail and 500 users are on fortimail. The MX will be pointed to fortimail cloud instance.

My question is, has anybody used fortimail server mode in hybrid environment. If yes can someone guide me what setting needs to be done for achieving above query.