[Baertram]

Not automatically.

Edit:
Oh and I think the main problem will be that you can ONLY be in 5 guilds with 1 account so it would not even work or show up properly.
So the below will not work at all "ingame" as the addon will not be supporting more than 5 guilds + it will most probably cross check the unique guildIds of the account, so leaving 5 guilds and not joinign new ones will not make it to work with manually added 5 guild's data you are no member off!

To achieve to see this you'd need something like Tamriel Trade Center and upload the data of all 10 guilds, so you are able to see the values online at their website e.g.


My answer was:
Logout before or your data files will be overwritten with next reloadui/logout:
You'd have to open the SavedVariable files (and I know there can be quite a lot, and I do not know where the data is tored in detail as I do not use MM), check for the tables with the server and accounts, copy the whole { ... } tables from the guild data of these accounts to the other accounts (to the subtable where the guild data is stored).

Maybe the files will become too long and break this way as the game cannot handle too big files.
So backup the files before changing anything.

And as I said: I do not know where exactly the data you need is stored, in what file below what table name.
Better ask the author in the addon comments, or maybe someone there knows how to achieve this.