Well, sorta. If you are an AP holder, you can get PhotoPass added on to the AP for $99. The PhotoPass is good while the AP is active. If you have more than one AP in your group, you only need one person to have the PhotoPass add-on. We've done this for a couple years now, and have had large groups with us - and all the photos taken were available for download to the
MDE account of the person with PP (and then those photos can be shared with everyone later). I'm not exactly sure what's involved in having it added after you purchased, but I expect it can be done.... since we're familiar with PP, I'm not sure if there are any DVC/AP discounts for MM. But PhotoPass has been priceless for us - pictures by Disney photographers, ride photos, we did Capture The Moment (all those pics were included), etc. Hundreds of family photos from individuals to the entire group - make sure you get it!
Not sure if that helps you out or not! Have a great trip. The memories we have from several large family trips are amazing.....