SQL Server Reporting Server (SSRS) separation of dev, stg, and prd data

I have a single SSRS server available to me (it's a HA cluster) and am looking for a solution to logically separate dev/stg/prd data that isn't too burdensome to maintain. There is no option to stand up another server or use VMs. One of the original ideas was to use schemas, but I think this would require a set of queries customized for each environment. Ideally, changing the pointer between instances (e.g., from stg to prd) would be quick. For example, if I could just change the connection string without modifying anything else. So, maybe we need to set up additional databases if SSRS supports this. I'm struggling a bit to articulate this point, and I may not even be on the right track. Also, I'm a guy that sometimes works with databases and has a working knowledge (hopefully) of MS SQL/SQL, but I do not have the expertise that comes with time.