Not knowing your experience level, I would suggest looking through the FMP help section on the topic "Value Lists".
You would be looking at a Value List, based on a field, using autocomplete.
If the help section is confusing or you find it hard to implement, let us know how we can help.
Note: the selections currently coming up in the fileds you like are likely Value lists based on that field. The field is probably set as a dropdown with autocomplete using that value list.
Additional Note: If you have to do the repeated data entry very often...a tweak to your Dbase design may remove the repetitive data entry altogether...but that's a bit more complex and would need more info about your current design and operation.
Very nice - it was easy after you gave me the right words to look up on the search - thanks alot!