Without photos it is tough to help you with design alternatives. However there are a number of 'alternatives' to beacons that might work for you.
There are what are known as 'drive over' fixtures but be prepared for sticker shock
There are shielded ingrade well lights. I know that Copper Moon, Nightscaping, and others have them.
There are shielded fixtures like the NS INTEGRAliter which do work to delineate an area, path, edge etc and yet have no line of sight to the lamp. (Brass INTEGRA's are currently not in production and unavailable.)
I am working with a couple of other Manus now to develop a shielded fixture like the INTEGALiter which promise to be smaller, more rugged and more easily installed.