I would open a ticket on all of your toons.

Specifically asking that a note be made that your accounts are being multiboxed by the same person.
Mention Blizzard can check that each account is run from the same IP address.
And that they each have the same registered address on them.

I have five different B.Net accounts, with one Warcraft account per B.Net.
Whenever I do transfers, I mail from my banker to a character on the same account who belongs to the team that needs the gold.
That toon then distributes the gold to each character on that team.
Have done that with gold for Epic Flyers, on multiple teams.