Just set for placemark access level (Placemark Details -> Appearance properties -> Access)
After that enable filter in map details (Map Details -> Advanced options -> Placemark Filter, set it to "Show placemarks using ACL")
If I'm correct, the "Access" will be in each placemark? In other words I will have to set the access level in each placemark? What if you have more than a 1000 placemarks? Will I have to set the access in each placemark?
Not sure if it's possible, but to gave an "Access" option within each group? This way it will be easier to control an entire group of placemarks?