You could use pin behavior to make them move together or move each of them same way with something like pick by evaluate or pick by comparsion. Not sure how to do smoothly such a specific distance. CustomMovement behavior might be useful if you can do some math and figure out how much and how long you need to accelerate and decelerate to move 20 pixels more smoothly than just at constant speed.
Many ways to move sprites simultaneously, but you can use this,
1)Add Instance variable to sprite (InitialY) 2)On start of layout (or any triggers you want) - Set Inital Y to each sprites 3)If Sprite.Y < Sprite.InitialY (Sprite First Y) + 20 (Distance to move), Set Sprite.Y to Self.Y + 20 * dt (it will make it move smoothly)