Android Contacts Groups Management

Question

Hello I am trying to write an android app that will supply contact data to a pc application via wifi. This is my first app and I have spent the last 4 days to find a safe way to manipulate contacts groups. To be more specific:

1. I am using sdk version 2.1
2. Emulator does not have contact groups functionality but this is not trivial
3. When I am exporting contacts from my device to sdcard (with the export functionality) it does not export any group information.

So my question is: Is there any documentation about contacts groups manipulation? Why is this feature so difficult to implement?

Thank you very much