Grid associated records - MS CRM 2016 online

Hi,

I have a requirement that needs to show the associated records in a grid depending on a record in other sub grid on the same form.

eg:

      Grid 1 -  UK (if i select here UK Record - Grid 2 should display 2 records -London,Leeds)

     Grid 2  - London

                 - Leeds

Any idea would be much appreciated.

Thanks,