Assign Multiple Masks to SKCropNode - swift

Question

As an example, I have a circle which travels to the left and then the right on the screen. I want the circle to only be visible if it is inside two specific squares (maskNodes). I'm using SKCropNode to try and achieve this, but the SKCropNode mask only lets me assign one mask. Does anybody know a way of assigning two or more mask to a SKCropNode, or if it is even possible to do so. Thanks!
override func didMoveToView(view: SKView) {
anchorPoint = CGPointMake(0.5, 0.5)
backgroundColor = UIColor.whiteColor()
let mask1 = SKSpriteNode(color: UIColor.blackColor(), size: CGSizeMake(50, 50))
mask1.position.x = -100
let mask2 = SKSpriteNode(color: UIColor.blackColor(), size: CGSizeMake(50, 50))
mask2.position.x = 100
let cropNode = SKCropNode()
cropNode.maskNode = mask1 // && mask2
addChild(cropNode)
let circle = SKShapeNode(circleOfRadius: 25)
circle.fillColor = UIColor.blackColor()
cropNode.addChild(circle)
// Move Circle
let moveLeft = SKAction.moveToX(-frame.size.width/2, duration: 2)
let moveRight = SKAction.moveToX(frame.size.width/2, duration: 2)
let seq = SKAction.repeatActionForever(SKAction.sequence([moveLeft, moveRight]))
circle.runAction(seq)
}

Answer 1

Figured it out, just has to add the two mask to a parent and then assign the parent as the SKCropNode mask.
override func didMoveToView(view: SKView) {
anchorPoint = CGPointMake(0.5, 0.5)
backgroundColor = UIColor.whiteColor()
let maskParent = SKSpriteNode()
let mask1 = SKSpriteNode(color: UIColor.blackColor(), size: CGSizeMake(50, 50))
mask1.position.x = -100
maskParent.addChild(mask1)
let mask2 = SKSpriteNode(color: UIColor.blackColor(), size: CGSizeMake(50, 50))
mask2.position.x = 100
maskParent.addChild(mask2)
let cropNode = SKCropNode()
cropNode.maskNode = maskParent
addChild(cropNode)
let circle = SKShapeNode(circleOfRadius: 25)
circle.fillColor = UIColor.blackColor()
cropNode.addChild(circle)
// Move Circle
let moveLeft = SKAction.moveToX(-frame.size.width/2, duration: 2)
let moveRight = SKAction.moveToX(frame.size.width/2, duration: 2)
let seq = SKAction.repeatActionForever(SKAction.sequence([moveLeft, moveRight]))
circle.runAction(seq)
}