Ok. I do see that on the accounting code. Is it possible to do an addition or is it only one? Ie can I add my group to that line without removing the old one?

How do you find the right name for the group? I see the ID for my group, but the view is calling group groups="account.group_account_user". I can only assume that is the Accountant group as they are the only default group allowed to view this tab, but I do not know how to get that name for the group I've created.

Alright, first things first. In your custom modules you should only be able to override the entire "groups-attribute". So instead of adding groups, you create the entire definition again. Secondly, when trying to identify groups head over to the code for the account module. Find the directory named "security". Inside that there should be an XML file which contains the group names as well as their ID. In my case I found a record with the name tag "Accountant" and the XML-ID being "group_account_user". You can use that in your case. Note: In most cases you need the dot-notation to distinguish the difference in modules. So groups should become something like groups="account.group_account_user", where account is the module that you found the group definition in.