Posting Assignments to Google Classroom Topics

I would like to be able to add an assignment to a "Topic" I have already created on Google Classroom. Currently when assignments post, they are posted to the top of the Classroom page. Then I have to edit the assignment and send it to my designated "Topic" I want it to post under. This is just an added step and would be easier if we could assign what "Topic" the assignment should fall under when making the original assignment.