Zuul multiple wildcards and nested routes

Question

Using Zuul (version 1.3.1) I want to have the following routes config:

zuul:
    routes:
        serviceA: 
            path: /us/*/a/**
            serviceId: serviceA
            strip-prefix: false
        serviceB:
            path: /us/*/b/**
            serviceId: serviceB
            strip-prefix: false

I could not find a reference on how the path parameter is treated and supposed to look like. Zuul seems to work correctly in my environment, as I can successfully use path /us/** for example.

But multiple wildcards in the path do not seem to work. Is this supposed to work? What would be a workaround if not? Are nested routes possible?