Motion tracking range

Hi there friends, i have a question. Here i found solution of my problem, but I’m hardly figuring out how to do it in reality.

The goal is to make two camera solutions in one scene. One before zooming out and one after and finally joining it. Blender camera solver seems to have problem with changing focal point.

I already have perfect trackers (perfect for me), but i need to split camera solution process to two different camera solutions and finally interpolate them.

So, my question goes:

is there any option to restrict camera solution to enclosed range or split trackers so i can use tracker’s initial sequence independently on the late section?

Thank you for drop by…

-Sincerily Rhino-

E: Well i gave up after hours of suffering. Good news is that i understood concept of motion tracking in 3d.