Can an attribute be added to the criteria in a Filter List for mass assignment

Summary

We are trying to create a New List with Object Worker Assignment Extract but need Primary Assignment in the Conditions Attribute. It is not currently in the Drop Down. Can this be added? We are filtering by Department but have employees that have multiple assignments in various departments and the Mass Assign is adding the journey multiple times. We only want it added to the Primary. There are no other attributes that are common to exclude.

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