Appreciate Siddharth, Yugandhar and Samuli for your valuable suggestions.
It seems to be working now, I have actually given the "Second Level Relation Name" in the wire and maintained the wires to point to the Z copy and it worked. The attribute "Second Level Relation Name" helped me to avoid the dump I was getting while copying custom screen from country specific screen (instead of _xx), thus I need not to add additional fields for that country if I would have copied from _xx.
Screenshot of the wire setting is as shown:
