User Master Data Copy

Hello,

I would like to know if there is a standard option to copy a user from one client to another client where you can insert the user details rather overwriting it.

My scenario is:

User master data from a system ABC client xxx needs to be copied to a system XYZ to client yyy where I need users from existing yyy to remain in the system. Basically I need to bring the users from ABC to XYZ without overwriting the user data of XYZ.  Is there any standard option to do this?

Thanks in advance

Regards

Hari