Combining Two Accounts

Is it possible to wholly and entirely merge two "free" accounts into one upgraded accout, whilst maintaining ALL features and functionality?

Or is the only way to export/import with Excel, cross your fingers everything jives and then re-enter certain additional "notes" or "contact information" that was not designated in the exported Excel document?

The reason being we have two offices that would like to do a trial run with 3 users each before committing to a paid subscription.

Thank you,