Run WCF ServiceHost with multiple contracts

Running a ServiceHost with a single contract is working fine like this:

servicehost = new ServiceHost(typeof(MyService1));
servicehost.AddServiceEndpoint(typeof(IMyService1), new NetTcpBinding(), "net.tcp://127.0.0.1:800/MyApp/MyService1");
servicehost.Open();

Now I'd like to add a second (3rd, 4th, ...) contract. My first guess would be to just add more endpoints like this:

servicehost = new ServiceHost(typeof(MyService1));
servicehost.AddServiceEndpoint(typeof(IMyService1), new NetTcpBinding(), "net.tcp://127.0.0.1:800/MyApp/MyService1");
servicehost.AddServiceEndpoint(typeof(IMyService2), new NetTcpBinding(), "net.tcp://127.0.0.1:800/MyApp/MyService2");
servicehost.Open();

But of course this does not work, since in the creation of ServiceHost I can either pass MyService1 as parameter or MyService2 - so I can add a lot of endpoints to my service, but all have to use the same contract, since I only can provide one implementation?
I got the feeling I'm missing the point, here. Sure there must be some way to provide an implementation for every endpoint-contract I add, or not?