Hanging props from ropes

The rope entities are just for show, use the physics entities to do the actual movement.

If you just want the appearance of something hanging but not moving, you can position the prop so it looks like it's being suspended.

If you want to move it, do what henke said, but the ropes will not move with it. You can't parent rope entities in TF2, but you can use a logic_measure_movement to move them along with your prop. Here is a guide.

Is there a way you could import the rope entity from Opposing Force?

No, the rope entities in TF2 are limited because they were not programmed with the same support for parenting as ropes in HL2. If you use logic in game to cut a rope from its tether point, where the point entity is placed in Hammer, it will dangle down limply as you would expect, but it will not reset each round. Only Valve can program TF2, and its source code is not available. There are other entities that do not work in TF2, such as func_rotating, and the counter function of env_global.

I can remember having parented a rope before and using a ballsocket thing to make everything swing.