Slicer based default selection on another slicer

Hi , kompalli 

Thanks for your quick response. In my understand you can refer to this:
I create a table like this:

This means when we select the "a", we can just select the "4,5,6" and for your need , it will be selected by the "4" by defalut.

(1)We need to create a table like this:

(2)Then we create a measure:

Flag = 
 var _product = SELECTEDVALUE('Table'[Product])
 var _cur_month =FILTER(ALL('Table') , [Product] = _product)
var _min_month = MINX(_cur_month , [Month])
var _slicer =SELECTEDVALUE('Table'[Month])
return
IF( ISFILTERED('Table'[Product]) && _slicer = _min_month ,TRUE(),FALSE())

(3)Then we put the 'Table'[Product] in system slicer and put the other filed in the "Preselected slicer":

(4)Then we can get the result is as follows:

Thank you for your time and sharing, and thank you for your support and understanding of PowerBI! 

Best Regards,

Aniya Zhang

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