(1) For the purposes of this Code, a group of companies comprises legally independent companies whose centre of main interest is in Germany and which are directly or indirectly affiliated on account of
1. the possibility of exercising dominant influence or
2. their being under common management.
(2) A company and its personally liable partners is also regarded as a group of companies within the meaning of subsection (1) if these include neither a natural person nor a company which has a natural person as a personally liable partner, or the group of companies continues in this manner.