Coping a field values from form header to the form

[Naqibullah]

i have form named home page in this homepage form in the form header i have inserted some fields from some tables like province, district, community etc. these fields are unbound and are used for filtering purposes, when i select a province all districts related to that province displayed and when i select a a district all related communities displayed, there is a one to many relationship between district table and community table,

what i want is, when i select a district on the form header(it is unbound as i explained before) of this homepage form, the DistrictID should appear in community subform under DistrictID(as there is a one to many relationship between district and community)
please help me
for more clarification find the snap shot attached

 

[pbaldy]

If that is a form/subform, you'd want that field in the master/child link properties of the subform control.