Using GROUPBY with dynamic filter context

Hi all,

I'm struggling with the GROUPBY() function. I would like to group my data by ITEM and doing an average on the volume. The table is filtered by a slicer on the minimum date. It seems like the GROUPBY function is not considering the filter context as the average volume is the same with or without the date slicer.

Table:

ITEM | DATE | VOLUME

A; 01/01/2013; 50

A; 05/01/2013; 60

A; 05/01/2015; 70

B; 01/01/2013; 50

B; 06/02/2013; 50

B; 05/03/2015; 40

Here is the code I'm using.

=GROUPBY(
                   Table;
                   Table[ITEM];
                   "Average volume by item";
                    AVERAGEX(
                                     CURRENTGROUP();
                                      Table[Volume]
                                     )
)

I would like the GROUPBY() to group the table already filtered with the date slicer, for example Date > 01/01/2017.

I should end up with this:

ITEM | AVG VOLUME

A; 70

B; 40

It's not the case and it seems like GROUPBY  is ignoring the filter context.

What would be the right way to do it?

Thank you very much.