"Required" reading

I've still been thinking a lot about reading this week. In my sophomore class, we are in the middle of a novel which some students are enjoying and some are not. Although it describes a culture and a time period (pre-colonial Africa) which are both unfamiliar to my students, the novel contains universal themes (individual vs. society, gender stereotyping, tradition vs. progress) which are important for my students to grapple with and, I believe, are relevant to their lives.

Before we started, I did a number of pre-reading activities (opinionnaires, anticipation guides, "word walls" -- small groups of students respond to key words that reflect the themes of the novel, e.g. tradition, honor, freedom etc.). Their reading assignments consist of about 25 pages every other night -- which seems pretty light for the average 10th grader -- and we are doing a number of different activities to discuss and engage with the novel ( a sampling: small group discussions, whole class discussions, small group presentations, watching relevant film clips, choosing songs to reflect the themes of each chapter, writing original titles for each of the chapters, writing original animal myths etc.) My goal is to make explicit connections between the world of the novel and the lives and experiences of my students.

There seem to be three groups of students in the class: 1. those who do the assigned reading, enjoy it and actively engage with the class activities, 2. those who read solely to pass the reading quizzes and at times engage with the class activities and 3. those who don't like the novel or find it boring and see no reason to engage with the class activities.

What more can I do to engage groups 2 & 3? Is it naive of me to think that there is something I am missing or not doing that would make their experience of reading more fruitful and enjoyable?