See my recent answer here: http://drupal.stackexchange.com/a/55144/7153

But basically, you can use

[nodeaccess_userreference][1]

or

[nodeaccess_nodereference][2]

to acheive that access control functionality there.

Basically you could deny author access and control edit access with one multi-value reference field instead.

More info, including screenshots at first link.


  [1]: http://drupal.org/project/nodeaccess_userreference
  [2]: http://drupal.org/project/nodeaccess_nodereference