Automation rule to not override manually assigned ticket

We have many automation rules that do the basics (most all at order 100, they don't overlap in terms of service/offerings) that will apply to the Client Portal tickets.  However, we do have tickets that are created via TDNext and the Help Desk user creating them would then assign either themselves or the HelpDesk group during the ticket creation.  

The problem we're having now, is that after the user does that, the automation rule for that service offering applies and overrides what the user had assigned initially.

We tried a few rules already, but they didn't seem to work:

• rule at order 10 (so first) IF Primary Responsible has a value OR Primary Responsible Group has a value THEN (no changes) Stop on Match enabled.
• rule at order 10 (so first), IF Unassigned is False OR Group Unassigned is False THEN (no changes) Stop on Match is enabled.
• 2 rules - at #10 Primary Responsible has value and #11 Primary Responsible Group has value   -- same as first try but two different rules, thought maybe the OR logic was letting ti slip through.

Basically, we'd want a rule with a high order that does IF ticket is already assigned to group or user THEN just stop and don't process any more rules. Thoughts?