1 way ipip tunnel

I have a unit that has 2 internet connections.

1 is a 2 way 300k/300k connection and 1 is a 1 way 20mbps down only
with 2 different ISPs.

at the ISP with the 20mbps I have a mikrotik 532.

I want to setup 2 ipip tunnels to send traffic from the slow network and recieve from the fast network.

Is it possible with the one way connection and if so what would be the steps on getting this working.