Here are a few options you could use, depending on the context:
* Peal: This is often used for a set of church bells.
* Ring: This could be used for a group of bells, especially if they are hung together.
* Set: This is a general term that could be used for any group of bells.
* Ensemble: This could be used for a group of bells that are played together, especially in a musical context.
Ultimately, the best collective noun for a group of bells depends on the specific situation.