If you have more than one company or business units within a company, there is no ideal way to manage them with ArchiOffice Online.
Having said that, we have seen users still do it the following way:
You maintain different value lists selections for each business unit. For example, the ABT division could have ABT_Client, ABT_Vendor, ABT_Contractor, etc., while the DCI division could have DCI_Client, DCI_Vendor, DCI_Contractor, etc. This way, when you do a Contact Type fine, you can easily find the clients or vendors for the right division. You cannot hide the one type from the other division, so you need discipline.
Project Numbering and Project Name can be used two distinguish the Projects for the different divisions. For example, the name or number of the Project (which can be anything you want) could be "ABT 04-0023: Smith Residence" and "DCI 04-0020: Riverside Plaza", where the prefix in the name designates the business unit it is for. You have a maximum of 11 characters available for Project Numbering. You can use as many characters as you want for the Project Name, but keep in mind it will only display parts of it depending on where you are in the system or what Report you print.
Invoices can be printed on your letterhead, or you can modify your RTF Invoice templates, using a different one for each division.
Invoice numbering must then be tracked so you know this invoice number was for this business unit, and that invoice was for the other business unit. Of course the invoices will be linked to your projects, which you can uniquely identify for each division as described above.