Jim,
I would have to assume that there are as many eco-climates in Costa Rica as here in California. I have known of people planting cyms in the ground but the successful ones used raised beds and a light bark-type mix. Remember that most of these standards stem from epiphytic species and the only reason we hobbyists put them in pots is to keep them from falling over and or showing them off in the house or at shows or club meetings!
The biggest problem is that the plants and their roots eventually interweave and dividing becomes a real chore. They do make a beautiful display when in bloom on a semi protected hillside but I would generally discourage doing it for reasons of frost protection, bugs and fungus.
That being said, if you want to try it, go for it. If any of the plants are virused, the rest will probably get it too. But if you are not showing or obviously not taking the plants out of your yard, that you can live with too.
I have always been of the feeling that growing orchids is meant to make the grower "feel good". If you want to enjoy your plants in the yard in a natural setting, try a few out there for a season and see how they cope with your environment.
Good luck and keep us posted!
CL