Re: Parenting two objects so they don't seperate when camera moves...

I'm guessing the red traffic light is a 3D layer? If it is, you can apply your lens flare to a black 2D comp-sized solid at the top of your layers set to 'add' or 'screen' then use a simple expression to link the position of the lens flare (in 2D) to the position of the red traffic light (in 3D). Try applying this expression to the lens flare center:

l = thisComp.layer("RedLight"); //this points to your Red Light layer
l.toComp(l.anchorPoint); //this makes the Lens Flare's 2D coordinate line up with the location of the Red Light layer's anchor point in 3D

Note that the lens flare will 'attach' itself to the anchor point of the red light layer, so if your anchor point isn't where you want it you can use the Pan Behind tool (Y) to move the anchor point where you'd like it on the layer.

Darby Edelen