1) I you have item (like tcibd001.item) on the form, you can add field in DFE using the Add Table Field option and then select the tcibd001.item field which should open (you see a link there) the "related fields". If you have no (database) link to tcibd001 this is not working.
2) In the index mapper between MMT and Satellite you can tell which records to show in the satellite with the main record in your driver. Ideally the main index on the (standard) table contains the index on your customized table too, so you can make a 1:n link.
Also read Luke 24:4-8