Is it possible to authenticate HTTP traffic in an iRule against the 'tmsh list auth user' user database?

Is it possible to authenticate HTTP traffic in an iRule against the 'tmsh list auth user' user database?

I have a requirement to authenticate users but the client does not want a separate data-group of users to manage and off-box authentication is not an option. They have existing mechanisms for password control of the standard F5 admin passwords and would like to keep using that for authenticating web traffic. The users would have a 'No Access' role so they cannot use the F5 GUI or SSH.

Any advice appreciated. Thanks!

Dave.