Modify connection string to connect to read only secondary node of my SQL cluster

Hey All - 

I'm looking to limit my users of dynamic Excel worksheets to connect only to the secondary (read only) node of my SQL cluster to limit the impact of mass reporting on my in use primary database.

I'm trying to add in "applicationintent=readonly;" to the connection string in the dynamic sheet but that doesn't seem to retain.

Any ideas on how to modify the connection string to force the traffic to my secondary node?

Thanks!