To unlock this achievement you need to deliver cargo TO 4 of the 11 container ports in Iberia. The source & type of the cargo doesn't matter so seeking any jobs with short distances is perfectly acceptable to unlock the achievement.
The container ports are listed as the "TS Atlas" company. There are 3 in Portugal and 8 in Spain.
Portugal:
Porto
Lisbon
Sines
Spain:
Algeciras
Malaga
Valencia
Tarragona
Barcelona
Bilbao
Gijon
Vigo