Hi Trinec...
I have never personally seen anyone achieve that, but it is a nice idea, although I suspect it would take a major excercise in advanced scripting and/or functions to get it to work.
I did some experimentation a while back as part of a rather over-ambitious mission that I started creating in January last year (!). I successfully managed to script a way to get an aircraft to crash land and take off from an "unsupported" OFP airfield (only one is properly enabled for each island). After the plane had taken off, I wanted to invisibly transfer the crew into another plane, that was following normal waypoints, so I scripted a way of setpositioning the plane very high, ejecting the crew then forcing them into the new plane (all normally hidden by an information screen). When trying to get the sripting correct, I put a long delay between when the crew were ejected and free falling over the ocean, before I moved each one into the new plane.
...this got me think about the posibilities of trying to do the sort of thing that you are trying to achieve for a different sequence (although I did not pursue it at that time). One of the main problems that I have not found an answer to yet is how to change the "attitude" of an object other than a plane (like a falling unit, or even an object like a notebook placed on a table). To be able to get two or more falling units (or other objects) to be put in any sort of formation, it would need a very fast acting script (or preferably function) that could position each one so that its "attitude" (e.g. the direction of a line pointing from the units feet through his head) could be pointed in any direction in "3D Space" (or to any point on the surface of an imaginary sphere centred on the unit).
I will try and do a bit of research, but someone else my know something useful...