Hello, 

I am trying to restrict clients to modify to some stage.

I have managed to add a custom field in addition to stage_id:

The rule as follows:

1. Client new request should be at 0, and can't move from 0 to anything else.
2. Client can edit other fields while in 0, but can't modify anything else but stage once past 0. 
3. Support can only move from 0 to 1, 1 to 2, or 1 to 4. 
4. Client can move from 2 to 0, or 3. 
5. Once it is at 3 and 4, the record can't be modified by both parties. 

I was able to create custom field using selection, and using record rules, I have been able to restrict user from modifying 1, and 2, but the user can still move from 0 to 2 and 3, or back from 3 to 0. 

How do I restrict the new value from being selected? ​