Adding additional disk to an existing RAID 1 setup

I just set up a G-Raid with Thunderbolt 3 in RAID 1 on Mac. Is it possible to add a G Drive mobile drive to the set up in RAID 1? If it is how do I do it?

Thanks.

No you cannot add more drives to the RAID. The mobile would just be an additional drive that mounts on your desktop separately.