Go to Edit, then User Id List
Enter your list into the Alias field. Click OK and save it.
Next go to Edit, then System and create a new system. If you want use the same name and write over the old one.
Go to File, then New
Fill in the new system Name and click OK
Then save it, It will ask you if you want to overwrite it. If you do, then do it.
You can put a date on the end if you want to mane new ones to keep it unique or go back to the previous list.
Select Units, Select All, then Close
It will ask you if you want to save the changes. Yes of course. You should be done. Alias names should display.