Keying Set Problem

Is there a way to make a keying set so I can keyframe only a single property of whatever bone I am currently rotating in my rig. Meaning, that I wish to select a bone, rotate it in Z, hit I, select a set that keyframes ONLY rotation z (and leaves the x, y alone). I have figured out how to do this for a CERTAIN bone … meaning I can make a keying set by using the data path to TORSO->ROTATION.Z for instance … but I want a keying set that will keyframe only z rotation of whatever bone is CURRENTLY SELECTED. I hope that makes sense?? So I can select a bone, rotate it, keyframe only its Z rot, then select another bone, rotate it, and keyframe it’s Z rot only … I am close, but can’t quite figure it out. If I knew how to make a data path to the CURRENT bone, instead of a specific one, I think I could do it. Any advice?? Please.

I"m not sure if that’s possible in Blender…

without scripting…

There is a template example in the text editor, builtin_keyingset.py.
Though im not sure how to write a built-in keying set.

Probably be best to ask on the python sub forum.