Continue pipeline with output being 0 document

Hi everyone,
I am wondering how to pursue a pipeline that has no output document. Let me explain :
At the beginning of the pipeline I am using some mappers and snaps to check existance of records. When my first snap returne document, we continue, as validation 1 passed. Second check based on the document numbers in the output :

• if 1 document at least: full stop, we do not go further and stop the execution.
• if 0 document, then I want to perform an insert using an existing insert snaps.

How to do this given that there is 0 document and therefore I cannot continue the pipeline?
Thanks,