How can I map same rest path to different controller? (Spring MVC3)

I have multiple endpoints

1. /a/* => DispatcherServlet
2. /b/* => DispatcherServlet
3. others => CXFServlet

So I set

    <servlet-mapping>
        <servlet-name>DispatcherServlet</servlet-name>
        <url-pattern>/a/*</url-pattern>
        <url-pattern>/b/*</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>CXFServlet</servlet-name>
        <url-pattern>/*</url-pattern>
    </servlet-mapping>

And I made AController and BController.

a/* should be mapped to AController and b/* to B Controller

The problem is that there are same resource (a/login & b/login)

So @RequestMapping("login") cant be processed

I want

a/login => AController and b/login => BController

How can I map? Can I use parent resource(a or b) to RequestMapping?