So, a long time plot arc is coming to a head where the pack has managed to organize all the local packs to undo a wound on the Arizona/Mexico border. Specifically, all the werewolves (about 17 in total including the players) will be sieged by rampaging spirits of Wrath while the Ithaeur work together to perform a rite to reverse the wound. I do plan on having a servant of Asmodai, Queen of Wrath to show up to really give it an Oh Crap feel.
However, that still involves 17 werewolves with a good 5 or 6 of them stuck making Harmony rolls. The ultimate goal, of course, is to make the players feel they did right by gathering up all these Uratha for one goal, while still spotlighting what they are doing.I want the NPCs influence to be felt without detracting from what the players are doing as well as making sure the ritualists are not just throwing dice.
How do I make this an engaging event without bogging it down in rolls or underplaying how tense this situation is?
Ideas that I have had include having quiet time in between rolls where people are patrolling and watching out for rushes or scavenging for useful stuff. I was also considering rules hacking the heroic opportunities system from L5R to allow for set pieces (There's a break in the spirit line and you can rend the portal closed sort of thing).
Please note that while I know that War against the Pure has mass combat rules, I do not own that book. I will consider suggestions from that book, but I would prefer general or narrative ones.