As Andrei already mentioned - you need to generate the GET method of the newly created context field and in this method create logic to return text value for any other value of the context that you want.
For example (written from memory, might need some tweaks):
IF iterator IS BOUND.
current = iterator->get_current( ).
ELSE.
current = collection_wrapper->get_current( ).
ENDIF.
CASE current->get_property_as_string( iv_attr_name = 'SOME_PROPERTY' ).
WHEN 'value1'.
value = 'text for value1'.
WHEN 'value2'.
value = 'text for value2'.
WHEN OTHERS'.
value = 'text for others'.
ENDCASE.
You can do this using the DB SELECT of course or read text from a domain if needed. The above code is just a proof of concept.
regards