Which Table Controls User Access?

Hi everyone,

Im sharing some tables between installations on various sub domains, but have made a mistake (after being live for quite some time) and no longer wish to share user access settings, or roles between sites. I can see how to stop sharing roles, but which of the entries in this array relates to the actual access settings?

$db_prefix = array(
  'default'   => 'project_',
  'users'     => '',
  'sessions'  => '',
  'role'      => '',
  'authmap'   => '',
  'sequences' => '',
  'permission' => '',
  'profile_fields' => '',
  'profile_values' => '',
  'users_roles' => '',
);

Im guessing permission, but I can't tell.

Many thanks!