SHAPE recordsets with no child

[dicesare]

Hi all! Does anyone know a method to instruct SHAPE to not return parents
recordsets that do not have child recordset?

for example, using the following

SHAPE {SELECT * FROM publishers} APPEND
({SELECT * FROM titles} AS PubTitles
RELATE pub_id TO pub_id)

if a Publisher doesn't have any Titles related, that record should not
appear in the returned recordset.

TIA