Zonal stats by group for an ImageCollection?

[vishalm1975]

Hi,

I would like to generate zonal stats from Sentine-1 time series, but organized by classes within my feature collection.
Say I have a watersheds feature collection, which has the following columns: Name, Class, Area

I want to generate csv output which is a time series by Name and Class:
Date, Name, Class, Some_stat_from_Sentinel_ImageCollection

How can I do this?
Thanks,
Vishal