lookup on runbase dialog based on another field value.

Hi All,

My requirement is to display the corresponding lookup as follows which is similar to the lines on the create trade agreement form.

1. table--customer details lookup

2. group-- customer group lookup

2. all-- field is hidden

Refer screenshot below.

Any suggestions how to achieve this and also can you tell where the lookup for that is written. I couldn't find the lookup on PriceDiscAdmTrans table.