Transportation to Port Tampa from Miami, Ft Lauderdale etc

I am trying to set up some group transportation from Miami, Ft. Lauderdale and West Palm Beach to Port of Tampa for a cruise... The cruise is on a Thursday-Monday and I know most people would like to travel up Thursday morning so they don't have to have a hotel expense or miss an extra day off work by travelling up Wednesday... I was wondering if anyone had any suggestions... I've been googling and looking at various shuttle services etc but was hoping someone might have some ideas... It could be as few as 4 people from the area or as many as 20+ people from the area....