Populating a generator. Is it possible? - swift

Question

I have a generator that generates a circle(SKShapeNode) every 2 seconds from the y-axis. (Moves up). I would like to know if it is possible to populate this generator uniformly(every x number of points.
Here is my code for said generator:
class CircleGen: SKShapeNode {
var circles = [WhiteCircles]()
var circleTracker = [WhiteCircles]()
var generationTimer: NSTimer!
var circ: WhiteCircles!
func generateCircles() {
for var i = 0; i < 4; i++ {
var scale: CGFloat
let rand = arc4random_uniform(10)
if rand == 0 {
scale = -15.0
} else {
scale = 15.0
}
let circle = WhiteCircles()
circle.position.x = lineGen.position.x
circle.physicsBody?.affectedByGravity = false
circle.position.y = 35
self.circles.append(circle)
circleTracker.append(circle)
foregroundNode.addChild(circle)
}
}
func startGeneratingEvery(seconds: NSTimeInterval) {
let callGenerateAction = SKAction.runBlock { () -> Void in
self.generateCircles()
}
let waitOneSecond = SKAction.waitForDuration(seconds)
let sequenceAction = SKAction.sequence([callGenerateAction, waitOneSecond])
let circleGenerateAction = SKAction.repeatActionForever(sequenceAction)
self.runAction(circleGenerateAction, withKey: "generateCircles")
}
}
Will post more code if necessary. Thank you in advance.