two tables with dates one filter

Hi, I tried to get along with the forum but I failed, maybe you can help me:

I have a Table with actions which took place on spereate dates in specific regions:

Actiontable:

Action 1 - 01/01/2015 - region 1 

Action 2 - 02/01/2015 - region 2... and so on

And there is also a Table that defines these regions. Some attributes of the regions can change over time, so there is the following structure:

Regiontable:

Region 1 - Size x - ... - 2015

Region 2 - Size y - ... - 2015

....

Region 1 - Size x+1 - ... - 2016

Region 2 - Size y+n - ... - 2016

...

I can't just create a link between the dates of the actiontable and the regiontable because i have an n:n connection.

I tried to create a separate Table with the Calendar function to merge those 2 Datecolumns. 

But the sizes of my regions keep getting summed up. 

All I need is to have one Date-Filter that applies to all tables.

Thanks in advance!