I have two questions regarding Gain Resources, page 11:
1. Does a hero have to actually enter each room (but not necessarily explore/search each one) in order for the room to be included as part of a room group of the same color?
2. If one hero explores 2 yellow rooms, and the other hero explores 3 yellow rooms, and they are all connected, does the room group for both heroes contain 5 rooms?
1. No, room groups are made of connected rooms of the same color, that's the only criteria you need to check. So even if during a turn you enter only one room that is part of a 5-room group, you still benefit from the whole "size" of the group.
2. Yes, exactly.