A group of travelers pulling suitcases are making their way down a platform.
Two couples are drinking a lemonade.
A group of travelers may not necessarily be couples also they are either drinking a lemonade or pulling suitcases.
Either they are drinking lemonade while they are pulling their suitcases or the sentences are speaking about different groups of people
There is no contradiction because a group could be two couples and they could be drinking lemonade as they pulled their suitcases down a platform.