On has line of sight/ every tick distance sprite.x/y sprite.x/y
Set ...Ok on phone no c2 (clubbing is dull lol), i think it's system zoom layout x 2. And same applies with sprite 3. Problem you may get is when both sprites are on screen, so you need a pick closest. If you have full version, make the target sprites a family, then pick nearest family. Otherwise, something like:
Every tick set global variable to distance (sprite.xsprite.y,sprite2.x/y) and gv2 too distance(sprite.x/y,sprite.x/y)
Gv>gv2: set zoom 200%
Gv2 >gv: set zoom to 100%
Really hope this helps, any questions I'll try to help again