https://wiki.openstreetmap.org/wiki/Tag:route%3Dbicycle#Members
as well just "allowing" ways in route-relations and recommends for longer routes https://wiki.openstreetmap.org/wiki/Tag:route%3Dbicycle#Split_routes_into_sections
the usage of superroute to combine the sections. 
Read "international" in the context of the rest of the world, where a route of 1000 miles length is usually international.