God knows your intentions, even if you forget to announce them! Yes, you may pray for more than one person or thing at any time. Prayers are not divvied up among intentions: a third here, a fifth there. read more
Or you can pray that the Blessed Mother will do with the graces earned as she pleases (say: "I offer this Rosary for Our Lady's intentions"). The Rosary is a private devotion and no specific formula specifies when to say the intentions. read more