Reflect group, not the objects within.

I would like to reflect a group in illustrator but not the object within the group, but the objects have to rearrange to their new place.

This can be done easily with few objects manually, but if you have thousands of objects. The job can be very frustrating.

Is there a way to do this automatic?

little example:

Before                         After

< < < < <                    < < < < <

<                                             <

< < < < <                    < < < < <

<                                             <

< < < < <                    < < < < <