LARTC - Jun 2005 - Aggregate 3 internet connexions.

Hi,

I have 3 internet connexions :
Router 1 : 192.168.212.2
Router 2 : 192.168.212.3
Router 3 : 196.200.8.73

I can''t change IP adress of router 3 because I haven''t admin
password
and my provider don''t want to give it.

I want only 1 PC to aggregate the 3 connexions.

How I can make that Router 3 work on my 192.168.212.x network?

Thanks
Jeremy