Default [Q] Back Key behavior can be modified?

So i have a galaxy s4. i had a idea, about pausing the process when leaving an app when hittin back button instead of destroying it.

when we open any app , bbm, facebook. games, twitter por example. and when we go out from it by pressing continously the back key, when we try to open the app again it will take more time than if we tap the home button.

basically home button tells android to pause the process and backbutton to close it which require more time when reloading the same app again.

i beleave this is not a remmaping thing because the back button will still going steps back in the apps, so, when there is no more steps to go back then it will pause it (not close it) ; home button will remain the same, pausing all apps to go home screen. and back button will pause only the one we are on (instead of closing it)

i repeat a lot the same thing because i want to be very clear. dont take it bad please.

Is this possible to make? may any of you give me some advices to do it?
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