To Copy a User List from Another Datasource

Log in to both datasources.
Do one of the following:

In the source datasource, select one or more user lists and select Copy. Then in the target datasource, right-click the User Lists node and select Paste.

or
Select one or more user lists in the source datasource, then press the <Ctrl> key and drag them into the target datasource. (If you do not press the <Ctrl> key, the selected user lists will be moved instead of copied.)

The Copy User List(s) dialog opens.
To retain the user list membership links, leave on User list membership links.
To retain the same user ownership, leave on User ownership.
Click OK.
The selected user lists are copied to the target datasource.