Integrating through a database or other data source is a time tested method of linking together services. For some services in critical paths that might not be

Integrating through a database or other data source is a time tested method of linking together services. For some services in critical paths that might not be the best way to do it but the pattern you've described here sounds pretty normal and standard. What exactly do you want to do to solve this problem? What's a "proper service integration?"