Setup one user with all the accounts required then go to Menu > File > Export > Export settings to xml file.
Select only Accounts.
Then have a look at the xml file in your preferred text editor. It is easy enough to understand the structure. Maybe easier for you to edit an xml for each user than to go through the whole account setup. Later you can import the xml using Menu > File > Import, and that will add the accounts to that installation of eM Client.
Possibly not what you want, but could be useful.