vpn

hello
i want to creat vpn.
my disign is that , we have three mikrotik A , B & C . A is a server.
my vpn is working on A to B & A to C.
but if i want to creat vpn between B & C . but it is not working
Can it is possible ?
ple. give me brief detail about that.


thanks

Please explain the scnario in details