Link objects to autoscaling boxes

[CADUS]

Hey! so I have the following problem: I basically want to customize an autoscaling text box, with the end goal of making a mogrt-file for overlaying text I can use in different videos.

I want the textbox to look like this in the end:

Someone in this forum proposed that the easiest way to achieve my goal is to just create the text box and basically "glue on" the frayed ends.

Now, I'm not familiar with expressions at all, but I figured out how to make the text box, but I failed at making the frayed ends move just as the text box does (or scale up and down in height with the text box). I feel like there is an obvious and easy expression for it and I'm just too new to the subject to know about it.

I would greatly appreciate a nudge in the right direction, I've been at this for hours now and it feels like I am just barely there...

[Mylenium]

Pseudo-code:

position+(width+offset)* scale

bLay=thisComp.layer("Box");
bWid=bLay.width;
bSca=bLay.transform.scale[0]/100;

mOff=250;

thisLayer.transform.position[0]+(bWid+mOff)*bSca; 

Mylenium