How to set parent bc field depending on on a checkbox field in child bc when applet is in query mode

Hi All,

We have a requirement as :

1) An applet has a field A with pick applet and a checkbox field B. Checkbox is a calculated field deriving value from its parent BC field value.

2) When the applet is in query mode, if the user selects Y in checkbox B , we need to filter the pickapplet field A records depending on the value of checkbox. if user selects N in checkbox, a different set of records should be filtered.

How to achieve this requirement? Either i have to set a profile attribute or update the parent field which is commonly used to filter the records in  field A and as a calculated value in field A.