Islander, man transporting group back (7)
I believe the answer is:
maltese
'islander' is the definition.
(I've seen this before)
'man transporting group back' is the wordplay.
'man' becomes 'male' ().
'transporting' indicates putting letters inside.
'group' becomes 'set' (both can mean a collection).
'back' is a reversal indicator.
'set' written backwards gives 'tes'.
'male' enclosing 'tes' is 'MALTESE'.
(Other definitions for maltese that I've seen before include "Island people - type of cross" , "Description of cross" , "Steal me for Mediterranean islander" , "Eg, native of Valletta" , "Someone from Valletta?" .)