Sidebar displays related links for Page

Building a site for a client that requires a list of PDFs, Videos, and other related documents be displayed in the sidebar for a specific page.

For example:
A page on aerospace should display aerospace related links in the sidebar.
A page on green technology would display a different list of related links in its sidebar.
etc.

I have been searching for a solution, but there doesn’t seem to be a way to do this. It also needs to be easy for my client to update.

I found a plugin, but it only works for 1 sidebar for the whole site, not a different list of content for each page.

Thank you,
B