One way to make the the integration less is to look for standards based data exchange. There are a couple of sets of standards that are relevant here.
The first is for the sharing of health worker data from the HRH viewpoint. For this, we have things like the Care Services Discovery (CSD) standard:
that is the basis of the OpenHIE Health Worker Registry – a centralized registry of health workers. There are also other standards like HL7 FHIR:
that can be used to represent that data.
For more traditional HR/Payroll functions, there are standards such as HR XML:
which can capture salary, time and attendance, etc.
If you combine this with the CSD standard, you will a very stable and powerful way to exchange health worker data.