What is pronoun for soldiers and prisoners?

The pronouns that take the place of the noun 'soldiers' and the noun 'prisoners', or the noun phrase 'the soldiers and their prisoners' are they as a subject and them as an object in a sentence.

Examples:

Their prisoners were very hungry. They had not eaten for days. (subject of the second sentence)

The soldiers are on duty. We will relieve them soon. (direct object of the verb 'will relieve')

The soldiers and their prisoners are hungry. They must be fed. (subject of the second sentence)

The soldiers and their prisoners have arrived. The camp has been readied for them. (object of the preposition 'for')