2 Calendly Instances to 1 Salesforce Instance

Hi, I IT at a University, I was approached by a school that has a Calendly instance that is not connected to Salesforce asking if they could get connected. 

The issue is that we already have one school’s Calendly instance attached to Salesforce. When I ask google if it is possible it says it is, but checking other spaces I get conflicting information that this is not possible.  

Can you please advise on what would be the process to connect an additional Calendly instance to Salesforce?