Hi Santosh,
Thank you. I really appreciate your prompt response 
In such situation, we follow the similar import method as you have mentioned in second point.
We have one global Dev system (DevGlobal) and other child systems. The child systems are divided based on the geographical region.
e.g. Dev1/ Q1 for EMEA, Dev2/Q2 for APAC, Dev3/Q3 for America.
The custom auth objects are created for particular child system/ region (say for Dev1/ Q1 - EMEA).
Hence it is not recommended by client to push the auth object in the other child systems/ regions (say Dev2/Q2 - APAC, Dev3/Q3 - America).
Normally, we perform role change in 'DevGlobal' system and push the changes to child D and Q systems.
However if we get error occurs due to missing object in any particular system, then we import the roles selectively from Dev child system (Dev1, Dev2, Dev3) to respective Q system (Q1, Q2, Q3).
However we are searching for any solution or SAP note, by which we can import the roles from Global Dev system to respective child Dev and Q systems, without getting any error.