Displaying multiple relationships of Accounts and Contacts as one

Hello,

We have a situation where in our opportunity form, there are multiple relationships between Opportunity and Account and Opportunity and Contact.  This means that each relationship has to be given a separate subgrid and it also means that they are treated separately in third party plugins.
 

For instance an Opportunity may have a Manager (Account) and a Salesperson (Account).  However we’d want them both to be combined.

Can this be done any other way than using a javascript subgrid which 'steals' the values from the other subgrids.   Is there a recommended plugin?