Self-Directed Solo-K For Parent Co

Mat and Mark,
Thanks for all your work…both this and the MSB podcasts are my two favorites.  My questions is, my understanding is that if I set up a parent company that owns my other business entities/ventures, and those entities are paying management/consulting fees upward to the parent, the parent can have a solo-K even if one of the subsidiaries has a group 401k.  But now I’m being told that’s not the case on account of the group 401k already in place.  Please clarify ways in which business owners who have employees and a group plan may still qualify for a self-directed solo-K in their parent co.  Thank you!