Adding bills to invoice as an item

Adding bills to invoice as an item

I love that Zoho Books has a feature to add unbilled expenses to invoices, but I wonder if there is a way to add open bills to an invoice?

When I receive a bill from a subcontractor for a project, I need to add that cost to the invoice (plus a markup). I also need to know when I've paid the subcontractor and closed out all my expenses for a project or a particular invoice.

It would be very helpful if a Bill could be associated with a project the way an expense is, so that I could see outstanding bills by project, know which ones I need to invoice a client for, etc...

Right now, I am recording subcontractor charges as expenses (even though I don't pay right away), since there's no other way that I have found to associate these costs with a client. this actually works just fine for me, but the way Zoho is set up, it seems like it would be a useful feature to be able to assign bills to projects.

Thank you.