Hi LaurensPP,
Thanks for taking the time to comment on this thread about assigning more than one customer to a project in QuickBooks Online. I want to make sure you're connecting with the right team to get the answers you're looking for regarding this, and I'm here to help.
Given that you've mentioned QuickBooks Online Advanced and that I see you've made several posts and comments in the US section of the QuickBooks Community forum, I suspect that you may be using a US edition of the program. If that's the case, I recommend reaching out in the US QuickBooks Community to get more insight on whether this option is available yet for any of the US packages.
It's possible to switch back to the US QuickBooks Community by clicking the link in my last paragraph or by selecting the flag at the top of the forum window and choosing the US one. There are often differences between the US and Canadian versions of the software, which is why this step is important.
If you are using the Canadian version of QuickBooks Online, however, please note that Projects is available in QuickBooks Online Plus and that there isn't an Advanced subscription package for Canada. Additionally, projects can still only be assigned to one customer, so I'm continuing to encourage folks to submit feedback using these steps: How do I submit feedback? You can stay on top of new updates for QuickBooks Online Canada here: QuickBooks Online Feature and Product Updates
Wishing you the best!
