I would write and/or email all the HVAC contractors in the area.
The cover letter would contain informatiom on or a reference to the shortage of trained techs in our industry,and ask if they find this to be true.
try acca.org website ,see if there is a chapter in your area or nearby and contact them as well,asking that it be mentioned at meeting or put in there newsletter.
Check out the wholesale supply houses and distributors ask them for suggestions,and if you can post a notice on their bulletion board.
check some of the internet sites for HVAC jobs,on this site and others.