Cell authoring

[Gumomo]

We have an Excel file that several people in our office work on. The document has several cells where changes are made by several different users. When you roll the cursor over the cell, the name of the original creator of the file appears in a small pop-up window. Instead, I want these cells to display the name of the last person to edit that particular cell to display in that popup window

I've tried going through tracking changes but it doesn't seem to accomplish this task

Is there another way to do this

Please help.