Party question

So, I mostly know how parties and dungeons work, but I was curious, is it possible for a party to enter a dungeon just by one of the party members going in or does everyone in the party have to go in individually?

 

1 Person in a world gives a key. Then 4 people (including the key giver) are allowed to enter the dungeon before another key is needed. This does not change based on a party so yes, each party member needs to enter by themselves. In later, endgame content, raids require four people and do have all 4 enter at the same time based on one giving the required runes.