Adding participants to a lifecycle project

Hi EX experts !

I’m setting up an automation for adding new participants to my lifecycle onboarding project.

Basically, I want to include all new employees based on their start date (“Date embauche” in my example below)

Quite easy to configure.

My issue is : how I can avoid to invite existing employees when I’ll import them in the Employee directory ?

Conditions are limited to delays :

• I can’t set up a condition based on the date I launch my survey, for example.
• I can’t neither check if a metadata is existing or empty.

Here is a screenshot of the interface…
If someone have any idea