Group board provides temporary bridging for crew (9)
I believe the answer is:
gangplank
'temporary bridging for crew' is the definition.
I can't judge whether this defines the answer.
'group board' is the wordplay.
'group' becomes 'gang' (a gang is a group of people).
'board' becomes 'plank' (synonyms).
'gang'+'plank'='GANGPLANK'
'provides' acts as a link.
Can you help me to learn more?
(Other definitions for gangplank that I've seen before include "It's for (dis)embarking" , "Way on to ship" , "way to get on board" , "Aid to boarding" , "Temporary access to a docked vessel" .)