Need to find all sets of 2 capital words

Hello I need to find all sets of 2 capital words : So far I have:

([A-Z][a-z]+\s?){2}

But it does not work always. For Example with the string:

Expedition Runic Monster Markers

I expect to get :

1. Expedition Runic
2. Runic Monster
3. Monster Markers

I only get 1 and 3. But I also want to get 2. I'm really stuck here. Any help is appreciated.