How to use Invoice and CRM together without importing/exporting contacts?

How to use Invoice and CRM together without importing/exporting contacts?

I'd like what I'm doing in Invoice to be reflected in CRM, at least as far as the customers I've already set up in Invoice. Is there no interconnectivity between the two? Right now I can only see one way to populate CRM with my customers, and that's via export from Invoice and import to CRM. That seems kind of "broken" to me given that Zoho is marketed as a sort of "all in one" suite.