I need to create a RELATED LIST that would allow us to record and display when one Account/Company has a relationship with another Account/Company.  Any individual Account/Company may have multiple relationships with other Accounts/Companies and we need these connections to be visible in either Account/Company record.  

Though I assumed this could be solved by creating a custom module with a lookup to the Account/Company module if/when I add TWO Lookups to the Account module I am forced to create TWO different Related Lists.

The simplest real world background I can provide is that we deal with large investment firms and these firms may have or use one or more law firms, lenders, investment bankers, etc.  Conversely the law firms, lenders, investment bankers, etc. are also viable clients for us.  Knowing that this firm is working with that firm is very valuable in meetings as the resulting name dropping provides instant credibility. 

Please Advise.