Polymorphic question

Probably a dumb question but in polymorphic games, let's take Australia. Do you need to occupy all 4 countries with one army in order to get the bonus? Or can more than one army (that you control) suffice?
TIA.
TIA.
Conquer Club, a free online multiplayer variation of a popular world domination board game.
http://www.tools.conquerclub.com/forum/
http://www.tools.conquerclub.com/forum/viewtopic.php?f=341&t=232851