How to prevent drilltrough to empty target

Hi,

in my dataset I have two tables (A and B) in 1:1 relationship.

By the way, not all the items of A have a related item in B.

In a report page, I have a table showing the rows of A and one of the columns is the related B value.

I have also a button that enables the drilltrough to another report page with detailed information about a B item.

When the user selects a row with an existing B item, the button is enabled and the drilltrough works as expected.

By the way, when the user selects a row with an empty B item, the button is enabled as well and the drilltrough works too, leading to a detail page with a "null" element as drilltrough target, which is a behavior that I don't want.

Is there a way to avoid it?