TDBAdvGrid lookup/dropdown

We have bought TMS Grid Pack to replace TopGrid in our application, and now we are looking forward to implement 121 grids.

We are new to this, and before we start to implement we want to find «Best Practice» for especially lookup/dropdown with TDBADVGrid, and we need help with this.
Here is a simple example explaining how it works today (with TopGrid).
Imagine a table “person” with a column “post code” and a table “city” with a column “post name”.  The tables “person” and “city” are joined with “post code”.
If we know that the start of “post name” is "Gj" we write "Gj%" in "post name" and press F4.  Then we get a list (dropdown) with columns "post code" and "post name" including all "city" rows with "post name" starting with "Gj", and we can choose the “city” row we want.

Similar behaviour If we know the start of “post code”.  If we give "29%" we get a dropdown with all "city" rows with "post code" starting with "29" (and the dropdown includes both "post code" and "post name").
Probably there is a simple solution – but we just haven’t found it ;-)