How can we to avoid that a contact record enter more than once in the listener program

We have a program (INTEGRACIÓN_EDUCONTINUA) [Please view the Image 1], with a Listener which gets the data from a Campaign Responses (275) as Data sources [Please view the Image 2]. Because there are a lot of campaigns as data source of the listener, is happening that the contact records are being duplicates. So we need to avoid that a contact record that already enter in the listener program no enter again in the same listener program. 

Is there any way to mark these record contactos in order to avoid duplicates?