You can specify multipleGETroutes that map to a single action simply by adding more than one route attribute. This can be handy when supporting legacy urls. To specify the order of these routes, use the Order parameter. This is important because the first route will be used to generate outbound URLs.
[GET("", Order = 1)]
[GET("Posts", Order = 2)]
[GET("Posts/Index", Order = 3)]
public void Index()