is there a way to play a song for several slides within a larger keynote presentation?

Place the sound file on the slide and use Builds to change the images during the sound files duration.

Inspector > Builds > choose an effect

Delivery: by paragraph

more options > start build manually or,

use automatically; and select a delay (the amount of time the slides show). For example; if you have a 30 second sound file and 10 images, enter a 3 second delay.