Link-Group Asset Class, Depreciation Area & Depreciation Key

Dear Experts,

I am new to FI-AA Customization & have a basic query about Group Asset Concept.

I am working on Ecc 6.0 & for Country India.

I want to create Group Asset for calculation of Depreciation as per Income Tax Act. Hence there is just one Depreciation Area (for Group Assets) , but the Depreciation keys are different. E.d IN1, IN2 etc. (Country Version India)

Now the questions are :

1) Do we need to create different Asset Class for different Group Assets or to create just 1 Asset Class for all Group Assets.

E.g. I want to calculate Depreciation As per income Tax Act on Gross Block of Building, Furniture & Fixture, Motor Car, Vehicles etc. So I need to create separate Group Asset Class for each one of above or just to create one Group Asset Class.

2) If we need to create just one Asset Class for all Group Assets; how to maintain a Depreciation Key in OAYZ as there are more than 1 Depreciation Keys?

3) is there any other method / functionality to calculate Depreciation as per income Tax Act or Group Asset is the only functionality?

Thanks & Regards,