How to blocks clients between them in subnet

[Pol Hallen]

I all

I've a network 192.168.2.0/24 connected by routing to 192.168.1.0/24
I'd like blocks clients on 192.168.2.0/24 between then in same network.

So, client1 can go to 192.168.1.0/24 but can't see other clients in 
192.168.2.0/24. And so for all clients.

Any idea?

thanks!

Pol