Where condition in cascadingdropdown element

[mambanero]

Hi,

i have to filter my cascadingdropdown element with an instance sql WHERE. My question is: can i compare two element of differents tables?
For exemple
If i have two tables (persons, subscription) and the elements malefemale.persons and malefemale.subscription can i use in WHERE box an istance like this malefemale=malefemale.subscription (if the element to filter is in the persons table?
Thanks