If you are using manual flashes (Yongnuo make manual and TTL models) then the triggers you need will connect to the camera via a cable. The cables are cheap and can be purchased separately so you could play around with them before your "upgrade". The triggers only tell the flash that a shutter release has been made and that they should pop now, power and zoom settings are made manually on the flash.
As I only have manual flashes I can only guess that TTL triggers will work from the hotshoe directly, however, I don't think you'll be able to try them out on your Sony even with the adaptor as the TTL systems are different. TTL will tell the flashes the metering and give them settings to use as well as popping instructions.
Hope this helps, if not give me model numbers of flashes and triggers and we'll see what we can do! ;-)