You can group multiple materials by adding a tag to the materials. You can search for a tag on the tag search screen to display a list of materials that have this tag.
Suppose you add a tag such as the following: "_____ seminar reference book" or "A must read for _____ class." Then, after a tag search, anyone can bring up the same list of materials.
For example, try clicking a tag in "New tags," "Recent tags," or "Popular tags." Then, materials that have these tags are displayed.
You can register tags on the search result list screen and the bibliography details screen.