Trigger the Dunning at same level

Hello ,

     I have a requirement to trigger the same dunning level again for certain validation .For example I Triggered the Dunning level 8 and inside that level it triggers some activities  .when system trying to go for next level we need some validation (Need to check the whether the Service request has been  created  at 8th level or not ).If the validation failed we need to trigger the same 8th level again to create the service request for PDV(one of the activity ) .Is there any way to do this or any event to write the validation ?

Thanks ,
Pankaj