How To Set Post Ads to only appear in a few post category?

Hi,

My 'In post Ads' is ok, up and running, but how to make one particular post ads appear in a few post categories? I have 2 Post Ads created and have many posts. I dont want my parenting ad goes to my business online ad. Instead, I want my business online ad that I already created there to be on the business online post.

Thank you
Lina