No. Access ribbons cannot be manipulated or only very limited manipulation is possible.
What you can do is create your own group within an Access tab and in there you can create buttons / controls.
Create table "USysRibbon" in your database (Instructions) with following Ribbon XML:
<customUI xmlns="http://schemas.microsoft.com/office/2006/01/customui"> <ribbon startFromScratch="false"> <tabs> <tab idMso="TabHomeAccess"> <group id="myGroup" label="My Group" insertBeforeMso="GroupViews"> <button id="myButton" label="My Button" imageMso="HappyFace"/> </group> </tab> </tabs> </ribbon> </customUI>
For Office Ribbon adjustments Patrick Schmid wrote an AddIn. Further