How to do dynamic rope/line/chain which can follow nulls?

Thanks for the answer! I just find other solution. I'm setup a two of my object, rope and null. The important think is to put anchor points of the object in right position because over there will be anchor point for the start and end of the line. Next, by using expression connect line to the object and also null. Null should be in the middle and controll how heavy is the line (also by adding slider, I can controll this by slider or without slider by moving null around). It's pretty simple solution, and works fine. For expressions I recommend use gemini or some other ai software, this is very very simple, but I'm not using this kind of features much right now so it was very helpful!