For any project type, you can exclude participants who have previously participated in a study with your organization. This can be configured to take any participation history with your organization into account, or just participation over a fixed number of trailing months.
How to set up a participation history filter
Create a project
Complete Project Set-Up
Click "Save and Next" to go to the Audience tab
Under the Filtering section, open the "Past participation" section.
Does the filter apply only to actuals, or does it include those who have taken one of our screeners?
Only participants who have been paid by your organization will be affected by the filter.