Click objects to draw a line between them

Say i have a set of objects in a row, and below that is another set of objects. I would like to be able to click an object in the top row and have a line drawn to an object that i click on the bottom row. However, I do not want an object to be connected to more than one other object and i would like to also be able to disconnect objects from each other. I am new to javascript, so I am not sure how i would go about doing this (i'd imagine something with arrays, toggles, and line renderers, but i have never used either) Any help would be greatly appreciated.