In the RBD sim, I will recommend to use rbd packed object workflow rather than the rbd fracture object. In rbd packed object, you can overwrite an attrribute called "active", which allow you turn your RBD sim from inactive to active based on this attribute. Or if you are using bullet solver sop it's in bullet object tab.
So the idea is fracturing your geometry first and then pack them in the assemble sop. Then transfer your "infected" attribute to the points and use it as active attribute. You can use pcfind like you did in the solver or just a simple attribute transfer sop. You can then have something like when the infected is > 0, active = 1. If you have overwrite active turn on, chunks will start to fall when it detects your active attribute is 1.
Unfortunately I can't upload the file since I'm at work, but here is some information I found to explain the packed workflow better.