we have been using Zoho CRM for a few years now and would like to start using Zoho Books, but I have not been able to find a way to make it work for our use cases.

Background

1. We need to invoice from at least 3 different companies

2. All potentials and quotes for the 3 companies are in our CRM

3. We need to be able to link every invoice to it's corresponding potential

4. We need to be able to create partial invoices (like one on project acceptance and another on project commercial availability) and both must be linked to the same Potential

So I though if we create one Zoho Books Organization for each company and the link each one to our CRM.

- This would let us create invoices from each company covering item 1

- Now each Zoho Books Organization should only obtain data for certain accounts and their potentiles, quotes, etc. And I am not seeing how this can be done

- In the only Zoho Books Organization I've set up so far I can see that somehow invoices are being create automatically for Potentials. But what if I want to create a new Invoice and link it to a Potential, is that possible?

- Item 4, creating partial invoices I think would be possible, I just need to figure out how to do item 3 first.

This seems to work somewhat if one has only one Zoho Books Organization and integrates with CRM bidirectionally and then enables the Zoho Books menu in CRM. This way invoices can be created for a potential right from the CRM. 

But from what I have read it's not possible to achieve this menu integration from more than one Zoho Books organization, So this would still leave me not knowing how to create Invoices and associate them to a Potential in the other two Zoho Books Organizations. 

Thank you for taking the time to read this far :)
I'd be very greatful if someone had a solution / suggestion for us.

We'd really like to use Zoho Books if possible.

Thanks, 
Andi