Markers are 508 accessible - How can I change them

For clarity, Tab=the keyboard key.

While the tabbed interaction is technically accessible, it is NOT user friendly. It is easiest to understand if you try navigating one using only the Tab key. When you get to a tab/button, pressing enter will display the layer, but the next time you press Tab, you are taken to the next button, not the conrent of the revealed layer. You can eventually Tab your way back to the content, but how would a non-sighted person associate that content with a button he presses 10-11 Tabs ago.

However, if you Tab to a marker, the marker is highlighted. If you Tab again, the next marker is highlighted. If you press enter, the marker content is displayed and can be immediatly Tabbed into for the screen reader. The next press of the Tab key takes the user to the next marker. This is perfect behavior for people with visual and mobility issues.

Unfortunately, I just can't figure out how to emulate that behavior. I can add a custom button for sighted users and hide an invisible marker on top of it, but the live area to press is soooo tiny compared to the button, users might think it's not working. Any attept to alter the marker states makes them stop functioning using the keyboard only method. I'm so close to making it work AND highly compliant. Any isight would be most welcome.