It depends on what you want to do with it.
If you want the platforms to eventually roll over the pulleys, you'll have to work with the link/joints method you mentioned.
Otherwise, if you want the two platforms to just move up and down and stay on the same vertical path, you can simulate something like this using basic physics.
Write a function that determines the force applied on one platform, and have both platforms inherit this function (so you know what force is applied on a platform without the other platform present).
Link the two platforms together: Within the function you just wrote, write code that requests the current force that is applied on the other platform, then apply the negative of that force on the own platform.
Do this every physics tick, and you should have a working pully.
If there are any questions, don't hesitate to comment!