Extending an existing domain

Hi everyone,

I hava a question, that is how to add additional servers to an existing domain?

the concrete environment is：
there are three physical linux machines and i have installed weblogic on them, one of the machines as the admin server(have created a domain on it), the other two machines as the managed server, and have deployed the same services on them.

now i have two another new machines(nothing on them), and i want to add them as the manged servers to this domain and want to clone the deployed services of existing managed servers to the two new managed servers, that is the four managed servers are deployed the same services.

So what shoud i do? I would really appreciate any help regarding this.