Networker does it's lookup based on hostname and not the ip address. In your case you can do a relocated restore from the source abc to the destination xyz. This can be done both using the gui and command line.

In case of the gui, you need to specify the source client as abc and the destination client as xyz. Please look at the Networker admin guide for details.

While using the gui you need to use the command;

recover -c -R

If I remember right you need to use the -y flag as well. Would suggest you look at the cli guide for networker for details on this.

Yes, it is easily done in the Networker User program.

You choose

Recover From: abc
Recover To: xyz

you will need to give client xyz a remote access to client abc. you should be able to recover abc's data on to xyz. its a directed recovery scenario.