[Rivet] RIVET -- how can I access all particles?

[Andrey Loginov]

Dear Rivet experts, Dear Andy,

   I googled for quite a while but couldn't answer to this question:

   How can I access all particles? (not only the final-state ones)

   For instance, for ttbar production I'd want to be able to access 
information about the top quarks and W's -- is that possible? I understand 
that Rivet is designed for final-state information, but in case if there 
is a functionality like that it would be quite useful for some 
applications.

Thank you and Best Regards,
                 Andrey Loginov   |   Yale University (Physics Department)
                 Phone(work/CERN) |   +41 22 76 73641 (from CERN  7-36-41)
                 Phone(cell/CERN) |   +41 76 487 2288 (from CERN 16-22-88)
                 Fax              |   +41 22 76 68579