Guild expansion with another Guild house?

Hi I recently started a guild a noticed someone talking about another player in their guild, building a guild house. I was wondering is this possible, and if so does it enlarge the guild, and by how much? If this is not a feature is it likely to be? Looking for official answers please ;)
{Baits Dev trap with beer and waits hopefully :p}

no it will not make guild bigger

one guild house for each guild

Anyone can build a guild house on their island, even if they're in a guild. All it does is give them the capability to make their own guild. It has no effect on their current guild. Guilds can only be expanded using the items from the merchant.