Animation slider (driver?) Hello Blender Artists!

As said in my previous questions, I´m pretty new to Blender and 3D stuff; I made this very easy door animation you can see below a few days ago with simple keyframes for every single part, and quickly got tired of animating every single part again and again. 

For a single open animation (the ~four seconds you can see below) I had to animate 42 parts with 2-10 keyframes! And now think of an animation where I have to open/close this door four or five times... no way.

So I want to ask if there is a way to "pack" all those single animations into a slider or something like that, where you have a "0" value (closed) and a "1" value (open) you can slide along. I´ve heard about drivers, but only found tutorials for SINGLE objects, so that´s why I´m asking here.

Is there any way to combine these keyframe animations into one, compact control thing?



Thank you very much beforehand for reading this through!
For a compact "control thing" you can use the dope sheet view. This will combine all object's animation data into one window for editing. In the dope sheet view you can reverse the animation data (for the door to reopen after closing) and then simply duplicate this new set of keyframes and voila 4 cycles of the door animation. Then again, it depends on what you are wanting to use this longer animation for, nevertheless, here is an excellent tutorial explaining the dope sheet: https://www.youtube.com/watch?v=JIWd0xfzxIc