AAAHHHH!! Gotcha ...
I believe Custom Attributes are what you're looking for...
On the Repository Settings page, Add a custom attribute named 'AUTHOR', then click on AUTHOR to select it ... and to the right, begin adding Author Names as Values for that Attribute.
Now, in order to take advantage of this new attribute, you'll need to make some changes to the template you're using. Edit the header.html file and add a tag [ATTRIBUTE:AUTHOR] to the template where you would like a drop down list of authors.(You should also place a [LABEL:SelectAuthor] tag somewhere for the prompt and add an entry to App_LocalResources/Repository.ascx.resx for SelectAuthor.Text with the text of the prompt you want to display. If you need to modify the default class for the drop down, add an Object tag in your header.xml file named AUTHOR and you can set the CssClass or Width of the dropdown. (See Sort or Categories for examples)
Also, make sure that in your Form.html file you have an [ATTRIBUTES] tag so that when you upload a file you can check which Author to associate the file with. Now you can go back and edit each item and check off the Author for each one.
In the header you'll see a drop down list of Authors and selecting an author will filter the repository so that only items with that particular author's name are shown.
I know that's a lot of steps and details thrown at you, but give it a shot and if you have any problems, let me know and I can step you through it a little slower.