If you are parring through a GPU to a VM then it cannot be shared with another running VM. You can only use the sane GPU in two (or more) VMs if they will not be running at the same time.
Hardware pass-through is always a bit of a hit-or-miss scenario as it is highly dependent on your exact hardware, BIOS, Linux kernel and KVM versions (most of which are outside Limetech's control) Until you actually try it you can never be sure if it will work for you.