File Access Control Using Range

I have sheet where I need to restrict access to a select group of individuals. I have a formula in a select case statement that runs from the workbook_open event and have hard coded the names of the individuals who can access the file. If they are not on the list, they are prompted for a password. This works OK, but I have sheet that is hidden and want to maintain the list of users there and update the code to loop through the values in a named range. I have a snippet of the current code below.

Code:
Select Case function_name
Case Is = "user1"
Run "enable_access_code"
Case Is = "user2"
Run "enable_access_code"
Case Is = "user3"
Run "enable_access_code"
Case Else
' User not authorized or opened while not on company network
' Prompt for project password
form_Password.Show
End Select