With a date stamped survey , you can filter by "since" using the lmast action column.
Didn't work for admin import , don't know for admin GUI.
Assistance on LimeSurvey forum and LimeSurvey core development are on my free time.
I'm not a LimeSurvey GmbH member,
professional service on demand
,
plugin development
. I don't answer to private message.