Easy enough (for support) to set this in motion for you. The headaches will come later on.
If you ever take breaks or retroratchet, make sure to make parallel changes on both accounts. If you’ve got autoratchet enabled, life will be hard without rigging something via the api.
If you’re doing this because we don’t (yet) support multiple gmail accounts on a single Beeminder account, shout loudly. Related thread: breaking changes in gmailzero