Hello,
What you are trying to do is bound to cause trouble.
Try
Give a Cname to one of the two clients and backup under different host 
name-Enter the host name and ip under host file.
or
Backup each client to different Networker server if you have one.
haveing two clients for the same machine is ok, however, having secound 
client with same name on the same server which phsically is not the same 
machine, dont know, i have never done this, do you not have an option to 
rename one of the machine to something different ?
What method of name resolution do you use, if you create client via long 
name it should force host file to be read first, in this case DNS should 
not quiry other aliases of the client, otherwise it could casue issues.
One other way that i have tried in the past and has worked is using IP as 
Networker client name , give it a try.

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