convert from pro\E format in *.obj format

[jobbef]

Hi!
excuse me for my bad english. I must convert a model in Pro\E propietary format in *.Obj format, therefore the subassembly that are in the start model (Pro\E), when i convert there must be rappresented as single object. therefore i want ask if there is a plug-in or a particular software that can make what I want.

Thanks in advance.