Dual point to Single point Tracking? AND Changing Tracking Point Midway In?

To clearify, these a 2 seperate questions:

Is it possible to dual point track 2 points and then use the midpoint between them as a single point for tracking? Basically I have 2 tracking points, but the actual tracking point that's going to move them is the middle of the distance between them. No I don't expect scale and rotation to be available because there is 1 tracking point that's going to move my object.

Like lets say I'm tracking a point and then it disappears for what ever reason, it goes off screen or simply just disappears. Is it possible to change the tracking point midway in auto tracking? In a way where my doesn't object just jolt to the different tracking area once the tracking point has changed, and instead continues from where it left off as thought I started a new auto track. Basically I don't want the change in distance between the old and new tracking points to be accounted for.

I hope you can understand my failed attempt to put my thoughts into words.