Forcing a Client trough a VPN Tunnel

Hello guys and girls,

I have succesful established a IPSEC VPN Tunnel between

  • Site A (RB941-2nD)
    and
    Site B (FRITZ!Box 7590)

.
Now I want to force a Client to use the FritzBox as Internet Breakout and that all traffic is going through this tunnel.

How to handle this, has anybody a hint an a idea for me?

Thanks and regards,
Rene