🚀 go-pugleaf

Questions on Cisco setup for subnetting:

We want to setup subnets on our company net. We have the class B address
131.195 and we would like to split it into subnets having up to 512
hosts on each of the 126 subnets. We won't use subnets with all 0's or all 1's. 
 
The site A is already connected to the internet as shown.
We want to add site B and site C and allow them to go to the Internet.
Is it possible for the traffic of site B and C to travel on site A cable
to reach the Internet via the site A subnet (and cable)?
Do I need to have anything more than the addresses, masks and broadcast?
What should my broadcast be: 131.195.255.255 ?
We have many Suns on these networks all running SunOS 4.0.3.

                                 INTERNET 
                                    ^    
                                    |    
                                    |    
                             serial |    
                                 _______ 
                                |       |
                                | CISCO |
                                |_______|
                                    |  ip      = 131.195.2.51
                                    |  netmask = 255.255.254.0
                                    |     
   Site A 131.195.2                 |ether 
   ______________________________________________________________________
                ether |                           |ether                     
                      |                           |                          
                      |ip = 131.195.2.52          | ip = 131.195.2.53    
                      |netmask = 255.255.254.0    | netmask = 255.255.254.0
                   _______                     _______                       
                  |       |                   |       |                      
                  | CISCO |                   | CISCO |                      
                  |_______|                   |_______|                      
                      |                           |                          
               serial |                    serial |                          
                      |                           |                          
                    Site B                     Site C                        
                  131.195.4                  131.195.6                       
                                                                             
                                                                             
                                                                             
--
   Clement Vaillancourt,             |   Institut de Recherche d'Hydro-Quebec
   Network Manager                   |        1800 Montee Ste-Julie, Varennes
                                     |             P. Quebec, Canada, J3X 1S1
   Email: vaillan@ireq.hydro.qc.ca   |  Tel: 514-652-8238 / Fax: 514-652-8309