Using a measure to filter in Looker

[BrittanyWP]

I am not able to filter by a measure in Looker. 

For example, we have set up a measure of how many staff members a business has. I want to filter how many businesses have two or more staff members. 

This is how the measure is set up in LookerML:

measure: count_unique_staff {
group_label: "@{gl_counts}"
description: "Distinct staff user count"
type: count_distinct
filters: [pk_transaction_uuid: "-NULL"]
sql: ${user_uuid} ;;

No matter what number I put into the filter for unique staff members, the number of businesses does not change.

Please send help 🙂