I am trying to create a custom approval loop for K2 articles. I planned to use extra fields as different status groups, but could find no way to have different permissions for extra fields in the same extra fields group.

For example, I want 2 extra fields :
1) dropdown field for authors to choose a status
2) dropdown field for admin to choose a higher level status. (author has no privilege)

How to accomplish this? I don't think there is an easy way.

I tried installing "Additional Categories for K2" to add extra categories and use extra categories as a sort of status, but the additional categories was tricky and it needed hacking of core code.

I'm looking into using "Inceptive Multiple Extra Fields Groups for K2", but think I will find the same problem.

Thanks for any help!

This can probably be done by creating a lot of new categories, but that will require more categories than I want to manage.

I think you need a custom K2 plugin for this.

You need a new status besides published/unpublished called let's say pending. By default authors/managers will not be able to publish items and only admins will be able to change the pending status.

As I said before this has to be done through a custom K2 plugin. In your position I would also look at the JED for such an extension.