How to merge objects in Unity?

Question

Unity

I just started to deal with Unity, there were difficulties with grouping objects, for example, with a price of 4 cubes, it is necessary that they behave together like a beech, as if they were "glued together". But at the same time, so that each object individually could have its own Constant Force component. Roughly speaking, each "cube" should represent, from the point of view of physics, something like engines on a quadrocopter. "Glue" seems to work, but as soon as you add a separate rigidbody to the cube, the whole structure falls apart. What can be applied to "fasten" objects?

Answer 1

https://www.google.ru/webhp?sourceid=chrome-instan...