Set 4 different sprites and pair by color or variables numbers
if player is colliding with 1 make player invisible add a timer of 0.5 secs and move the player to 2 for blue
if player is colliding with 3 make player invisible add a timer of 0.5 secs and move the player to 4 for green
I’m sure there is a lot of ways to do this but this should work
Other source here How to create a portal : GDevelop 5 - YouTube