Separate services in an existing MS environment

[ECB]

Hello

I want to know how to extend an existing multi-server installation to handle larger workloads.

In a ZCS multi-server environment, in case the servers can't handle the growing demand, how can I move certain services to new physical servers without re-installing the whole multi-server environment?

Let's say I discover the AntiVirus, AntiSpam and MTA services are too heavy for the existing servers and I want to move these services to new physical servers. How do I do that without breaking the installation?

Thanks in advance.

[ECB]

OK maybe I was being too general -

Let's assume I want to add a new MTA server to an existing 2 server ZCS multi-server environment. How do I disable the MTA service on both servers and route them to the new MTA server?

I tried adding an MTA only server to the multi-server environment and then disabled the service on the first two servers, but I can't configure the servers to even use the new MTA. When I start typing in the "Web mail MTA hostname" field, I immediately get the message "Value did not match valid values.". The hostname I type is valid and is resolvable.

What am I doing wrong?
How do I tell the exisiting servers to use the new server for the MTA service?

(BTW - I updated my ZCS version in my signature)

The funny thing is that the actual Multi-Server manual gives an example of different ZCS deployments (see "Configuration Examples") where separate servers perform different roles, but I found no instructions on how to actually perform such configurations.