In passenger manifests into the United States during the 19th century, there are often notations about the luggage of those listed on the manifest. There are not always details about luggage, but some lists will indicate how many cases or bags a person has. Sometimes if one looks carefully, ditto marks may indicate a "group" of people having the same number of items. That could be a potential clue that people are travelling together and may have some connection.
It could be a clue.