I found a solutionhere but it is a bit more complicated then i first thought.
You first have to apply an constraint on the parameter in my case:
[Orders.Order_Participant/General.Participant/General.Participant_ParticipantEmployee = '[%CurrentUser%]']
Then you have to go to the domain model to apply these constraints to the user roles that require these constraints. You don't even have to have the participant parameter on your screen.