dual WAN ( direct and sixxs tunnel)

RouterOS Beginner Basics
1

Hi folks,
i changed my ISP provider. This provider (Unitymedia cable) has only IPV6. Now my question:
Regarding to the ISP’s network, ist it possible to make a design as follows.

  1. WAN (DHCP) to the Fritz Box (6360 cable modem router) for the whole outgoing traffic
  2. SIXXS Tunnel ( IPV6) only incoming trafic for outside access to own private network.
    The reason is, that i only want to handle the incoming over the tunnel. The outgoing should go directly, to keep latency low and have the full ISP bandwith ( 150 Mbit). Has anyone realised this design already or better to ask. Is this possible.

Thanks

Alex