How do i delimit the multivalued fields in Splunk?

Hi, I have a search which produces a table and one of the column Username contains multiple values. They are kind of aliases for the same user. I need to delimit them using a comma separator. How do i achieve that please? Username test1@gmail.com test2@gmail.com test3@gmail.com test4@gmail.com I want something like this - test1@gmail.com, test2@gmail.com, test3@gmail.com, test4@gmail.com