As a parent of teenagers and a middle-school teacher I can tell you that this is a great idea. Try. Try getting teens to talk. Try getting them to talk about important matters. Try getting them to talk about suicidal thoughts.
It's not easy but it does work and it does help. Teenagers who feel this way are usually desperate for the chance to talk to about it. The first thing they learn is that they are not the only ones who feel this way. This is half the battle, sometimes. Often just the fact that the teacher/parent/adult is trying means the world.
And keep trying. Don't stop trying just because the standard line is that it's impossible to get kids to talk about important matters. That attitude is half the problem.