While in the Content Manager, scroll up to the top of the page to "Show and Sort" and click. You will see a menu for:
Show All
Show Amazon Items Only
Show Kindle Items Only
Show SD Memory Card Only
You will want to use "Show Kindle Items Only" and "Show SD Memory Card Only". Unfortunately, you can't combine the two but have to bounce back and forth between them but you'll have fewer pages to deal with and no Amazon stored items will show.
BTW, welcome to MobileRead!
