I have a line of SKSPriteNodes, I want those nodes to move from top of the screen to the bottom, those nodes are not at the same CGPoint, they are behind each other forming a line, When I use the normal SKAction.MoveToY() and I give it duration they move at variant speed in order to all arrive at the same time, What I want is for all nodes to move at the same speed and arrive one after the other, keeping thier line form. 

Here is how I create them:

```
     for i in 0...5 {
         let enemy = SKSPriteNode(imageNamed: "Enemy")
         enemy.position = CGPoint(x: size.width / 2, y: size.height + enemy.size.height * CGFloat(i))
         addChild(enemy)
         enemy.runAction(SKAction.moveToY(0 - size.height, duration: 5))
        }

```