Gitolite user/repositories management

Question

I have gitolite server running just fine. The number of git repositories is increasing every week. My gitolite.conf was getting messy so I decided to use aliases. however, there is something which I cannot understand.

I have following config:

    @users  = u1 u2 u3
    @admins = a1 a2
    @repos  = repo1 repo2 repo3

In the easiest scenario I grant RW+ access to @users and R access @admins with following config:

   repo @repos
     RW+ = @users
     R   = @admins

Now, I would like to deny access to repos repo1 and repo2 for user u1 but give RW+ access to repo3 .

How would I achieve this gitolite.conf ?

Of course I would prefer not splitting repositories configured in @repos alias.