Post deprecation only in selected periods

We are looking for a depreciation key that covers the following requirements:

1) Asset do be depreciated by 50% in the first year, 30% in the second year and 20% in the third year.

2) Depreciation only to be posted in the periods the asset is used "(season"): Only December, January, February and March

3) No depreciation posting inthe other periods.

Remark: Company Code is assigned to a year specific fiscal year variant.

Regards

Klaus