"Escape"-Condition on Interface
 

Hello, due to backflow I've extended my pipes outlet by severel metres. I have multiphase flow with a lagrangian particle phase. However the trajectory of the particles in the extended part is completly irrelevant for my studies so I'm trying to give my Interface the condition "Escape" (I have one way coupling so it should not make any difference). However since it is an interface boundary it doesn't work. Anybody know how I can fix this? Basically what I want to do is to remove the particles after they have passed the relevant parts. It would save a lot of time.

Edit: at the moment I'm using an Internal Interface