How to keep two slicer have same value

I have 3 tables, relationships like this, Date1 and Date2 table will create slicer for user pick different date to compare value, Date1 and Date2 table have same column and same value, but when show on slicer, they will show different value, because they have different relationship, date1 show on COB Date slicer, this slicer will just show matched date with Fact table,  Date2 will show on Pre COB Date slicer, this will show all the value, now I want to make Date1 and Date2 slicer keep same value, How should I do it, Is anyone have good idea, Thank you