product families and design drilldown

Hi gurus,

we have product family and product design as characteristics in the planning book and below is the behavior that i see. Is this standard ?

When selecting multiple product families within the header, no further drill down is possible without viewing the product design for all product families.  In other words, if I select family 1 and family 2 as my families and then select "Display All" under the product design level, all designs for all families explode out instead of my manually selected family designs.  Additionally, if just family 1 and family 2 is selected as the family, even manually selecting the designs specific to these families still explodes the design level to all families and all designs. can anyone please share some thoughts on how to address this issue.

Thanks

Ravi