Welcome to the Community,

just creating a VLAN may not solve that.

How does the network configuration on the hosts look like today? Are VLANs already configured, or is everything (VM port groups, and VMKernel port groups) in the same subnet?
How do you want/need to access the hosts/VMs, i.e. are you going to route the subnets, or will the systems remain in a separate subnet?

André