Related content view based on tag field in comment

I have been tooling around trying to create a related content view. I found this set of instructions for a related content view which were very useful. This works nicely for tags on a node.

However, my case is a little different. I have a tag field (for article taxonomy) in the comments for a custom content type (essay) and would like to display related content (articles etc) based on those comment tags, not the ones on the node itself.

(i.e. A student writes an essay, a teacher gives feedback which includes topic tags that will then pull related content from the article database as recommended reading for the student.)

I had a stumble around, but didn't get very far with it.

Any help would be appreciated.