Is anyone familiar with statspack?

I have 2 separate ORACLE instances running on the same system. I installed the statspack using the connect / as sysdba login.

When I login using the perfstat account the program defaults to one of the 2 instances to provide performance information. How can I get information for the other instance?

I figured if I specify one of the instances during the login and run the install again like connect /@instance2 as sysdba, I could have the program installed separately for each of the instances but this doesn't work because I get disconnected from the session during the installation if an instance name is specified in the connection string.

If anyone is familiar with running the program on a system with 2 separate instances on the same machine that offer me any advice I'd sure appreciate the help.