How can I apply an action to several checked models

I’d like to be able to select several model items with a checkbox and apply an action to them.

I don’t want to add a “selected” boolean flag to the item’s model, because that “selected” state feels like it should stay on a controller. Also, in my use case, I won’t be able to overload the model with a new property.

Is there another way I can keep a template in sync with a list of checkbox items?