I'm assuming a user of the system can pick one of three paths:
- Start from the people and for each person see which actions are available on which account.
- Start from the accounts, looking/setting who has what access to it.
- Start from actions and see on what accounts they are available and who can perform them - this seems a bit less likely, but I might be wrong.
I'm also assuming you don't have to see the entire information together, i.e. see all the users in the system, with all the access types they have to all the accounts. If that's the case, it implies a grid component.
The solution that comes to mind is a master-detail with 3 interchangeable columns where:
- The first column would be the entry point (described above)
- And the second would be the "group by" which is also interchangeable with the final detail column
- First column is a list of users, which you can sort and browse simply by moving the highlight down the list.
- The second and third would be pairs of actions and accounts.
Interchangeable as we've mentioned (i.e. see all the accounts grouped by action, or all the actions grouped by accounts), assuming the first of the two can also be sorted.
In effect moving the columns account to be first, would change the "entry point".
Moreover, each element has a "go to" function, which means the user can go to a view centric around that element (i.e. if I was looking at John and noticed he had access to account 124255, I could easily navigate to that account and see a similar list of all accounts and users who can perform them).