ha ha....ppl seem to forget that working large muscle groups in compound movements help the rest of their body out...barring injury if you dont do squats then your basically just fucking around in the gym
If that was true then you would only have one "universal" chest excercise. Think about it. Why make so many different benches and machines if every exercise worked all the parts of the chest evenly. Bench, incline, decline, pec deck, dips--yes the overall chest is affected, but they all concentrate on one place more than another.
inner chest- medium grip bench press, dumbell flyes
outer chest- wide grip bench press
upper pec- incline bench
lower pec- decline bench
make ur chest workout hit all 4 of these
like for instance
3 sets wide grip bench press
2 sets medium grip bench press
3 sets incline bench
3 sets decline bench
2-3 sets decline
also upping the mass of ur inner chest will only make it look more like boobs but it actually looks good.