you can have an elastic provider, assuming you are using Pay-Go or Elastic Allocation Pools (enable it in general settings).
this means we'll deploy to one cluster until it's full, then overflow to the new cluster. you can also ask VMs to be moved from one resource pool to another.
To be able to do an elastic Provider, I think you need to use VXLAN to span the two clusters together.
more information on the requirements here