One account per company
If you want to register several companies at PriOffice, you need a separate account per company (per CoC number). After all, every company is a separate entity. You will also receive a separate rental agreement for each company, because the Chamber of Commerce and /or the notary will ask for it.
The cost of the business address is also per company, however, from the 4th company a discount of 10% is applied to the monthly Plus membership.
At several companies you only need one Postbox, in other words, you do not have to apply for it per company. So you can link all companies to one Postbox. However, you can also choose to take a Postbox per company. See here the differences.
To help you get everything right at once, the different options are explained in more detail below. So please read this carefully before you make the applications.