However, you could use some of these options depending on the context:
* A team of rescuers
* A group of rescuers
* A band of rescuers
* A force of rescuers
* A company of rescuers (if they are organized like a military company)
You could also use a collective noun that describes the specific type of rescuers, such as:
* A crew of firefighters
* A squad of paramedics
* A battalion of lifeguards
Ultimately, the best collective noun to use depends on the specific situation and the desired tone.