Render only outlet template if outlet exists

I have route 'A' and subroute 'B'. I don't want to render the template of Route 'A' if the subroute 'B' is accessed. But if am I not at subroute level, I want to render the template of route 'A'.

Is there a way to achieve this? I tried following for template 'A':

    <h1>Subroute</h1>
    

    <h1>Route</h1>

Pity enough this does not work (outlet is a 'magic' word, it is not a normal variable). I could do it by using css's absolute positioning, but I would like to use a more Ember way if that's possible!