it certainly is possible, and there are perhaps several ways to get the desired outcome (and several ways so that it is impossible to get it). your question is vague, the fact that H can be "any point" on D, and the fact that A is some point that we don't even know how far from d it is, makes being specific as to how to get the desired outcome very hard. do we have the freedom of choosing where we want A and H to be?