SOA: Extend SOA domain

Hello, Is it possible to extend a SOA domain to add additional managed servers to a cluster. We created a domain with 2 managed servers in a SOA domain and wanted to
 check if its a posibility or advisable to extend a SOA domain to add additional servers since its tied to MDS database.

 Also is there a WLST script for doing so? and how can be it be done when adding a remote managed server.
 
 Appreciate a response.

Thanks,
LR