Howdy! How would you suggest marketing a new service to a hard-to-reach audience?

Brief overview: I would like to market local, weekend yoga retreats to professionals in the oil and gas, energy, and finance industries. No long absences from work or family, and no long-distance travel. The startup is set up in Houston, but can operate in any city in the USA. Lots of different marketing and advertising methods are being tried (online groups, directories, online forums, linkedin, etc.), but I am pretty much throwing things to the wall and seeing what sticks. Any suggestions are appreciated. Thanks!

startup: bodyhugs: hug your body with movement and care

website: http://www.bodyhugs.org/

local health and wellness retreats in the USA