Admin note: Moving this to a different space.
You can do the following types of NAT:
- Many to One NAT (i.e. HIDE NAT)
- One to One NAT (i.e. Static NAT)
- Many to Fewer NAT (Basically HIDE NAT with a pool of addresses)
Note that Many in this case refers to objects of either type Network or type Address Range.
It is not possible to do a "one to many" NAT.
Without knowing more details about the server IPs on your end (are they in the same subnet, different subnets, or?) and the pool of IPs provided by the remote end (same question), my guess is you'll need multiple HIDE NAT rules to achieve a functional result.
It would help to have some screenshots of what you've attempted and what results were achieved with that configuration.