How to distinguish a part of 3d object?

Hello! I have a sphere (imported via FBX) with video texture - 360-degree video. I need to change parts of that texture when some signals (e.g. MIDI) are coming. Is it possible to select a part of 3d object (couple polygons) and apply different texture to it?

General idea - we want to make interactive sphere that reacts when user touches a touch panel which is a part of the sphere. Sphere has 10-15 touch panels in the bottom area.

I was thinking, maybe instead of changing existing video I can show some effect, like glow, over it. But still I need to understand how to address a particular area of the sphere.

Thanks for any suggestions!

A few options are to separate out the parts of the sphere that you want to map other things onto. Or use TOPs to place data over your 360 video at the spots where you want them to show up.