Keyframe Camera Position according to multiple Layer Positions using Expressions

[Johannes5C20]

I have a scene with multiple images positioned in 3D space and want a camera to move from one image to the next. I have a Null controlling my camera Positon and Orientation and every couple seconds I can just set a keyframe to match the position of the image I want the camera to look at at that time. However, if I move a couple of images around I have to set the keyframes for them all over again. I was wondering if there is a way to use an expression on my controller Position and Orientation so that every keyframe is linked to the specific images position. The cherry on top would be if it could assign the keyframes to the layers (they all have the same name with a number at the end) automatically depending on their number, but if I have to assign them once manually that would be okay. I would use Flow at the end to apply the same ease to all, so that would be important to still be able to do. I hope I could make clear what I'm trying to do, I'm not very versed with expressions yet.

Here you can see what the Comp looks like. The keyframes are set every 8 seconds.