Divide a network

[RJ <rj@jezuici.krakow.pl>]

I have a question:
There is a TPC/IP network a.b.c.192/255.255.255.240 for 16 IP.
The router is a.b.c.193 and everything works fine with the topology:

   +---> Internet
   |
ROUTER a.b.c.193
   |
 +-+-+
 |   +-- a.b.c.194
 |   +-- a.b.c.195
 |HUB+-- a.b.c.196
 |   +-- ...
 |   +-- a.b.c.214
 +---+

How to divide the network a.b.c.192/28 into two independent networks to
pass the second network a.b.c.200/29 via Linux routers and PPP?

            old network      new networks
           255.255.255.240  255.255.255.248
a.b.c.192  newtork0         subnetwork1
a.b.c.193  IP01             IP1
a.b.c.194  IP02             IP2
a.b.c.195  IP03             IP3
a.b.c.196  IP04             IP4
a.b.c.197  IP05             IP5
a.b.c.198  IP06             IP6
a.b.c.199  IP07             broadcast1
a.b.c.200  IP08             subnetwork2
a.b.c.201  IP09             IP1
a.b.c.202  IP10             IP2
a.b.c.203  IP11             IP3
a.b.c.204  IP12             IP4
a.b.c.205  IP13             IP5
a.b.c.206  IP14             IP6
a.b.c.207  broadcast0       broadcast2

ROUTER a.b.c.193
   |
 +-+-+              +-----+
 |   +-- a.b.c.194--+LINUX+
 |   +-- a.b.c.195  +--+--+
 |HUB+-- a.b.c.196     |PPP
 |   +-- ...        +--+--+
 |   +-- a.b.c.206  |LINUX|
 +---+              +--+--+
                       |
                     +-+-+
         a.b.c.209 --+   |
         a.b.c.210 --+   |
         a.b.c.211 --+HUB|
         ...       --+   |
         a.b.c.206 --+   |
                     +---+