assignment as a comment and not as a post in a channel

Hello, i'm a learning community and taking action is one of my priority for my students. we're an art school so our student post a lot. They have regular training and share the work they do on each training. I have approximately 200 different trainings so unless everything is mixed up in one or two channels, i would need to create 200 channels which is just overwhelming. I would like my students to share their work by commenting posts and not by creating a post in a channel. As soon as this is setup i would be able to move all my courses to heartbeat : )