Assigning Multiple Countries to a Value in a Filled Map

I am a complete novice with Power BI so I apologise in advance if this a very basic question. 

I'm trying to create a filled map to highlight the different countries a TV channel broadcasts to. It works fine when it only broadcasts to a single country but when a channel goes to multiple it will only highlight one on the map. 

I have tried keeping the countries in one column and separating them by a comma and I have also tried spliting them into different columns as in the example below, but it still only returns one country. 

Any help would be hugely appreciated.