Merging Guild Chats [Noob]

[Mor4Me]

Hi. I'm completely new at this stuff, but my guild has been at 500 members for a while and we have hoped to expand, but do not want to be limited by two ingame guild chats. Does anyone know how to make it so that everyone in each guild can see all the messages from their guild and the other guild as well, whilst being able to see who sent the message, as per usual? Thanks for reading this post, if it is also not possible/I could not possibly attempt to do it, also let me know... as I already mentioned, I am a complete noob at this stuff.