Stick to heavy pressing (overhead) and your shoulders will grow, trust me!!!
As for rear delts, they will get blasted when you do deadlifts and any type of rowing.
I used to try and hit each head of the delts when I first started working out. Then I came across DC training which focuses on HEAVY COMPOUND MOVEMENTS. My shoulder exercised consist of Military Press, Behind Neck Press, and DB Shoulder Press. My delts have made huge improvements since the switch. My front delts are alot bigger as well as my rear delts. And like I mentioned earlier, deads and row have taken care of my rear delts quite well.