Can xi and xi 3.1 coexist on the same web server?

Is it possible for a web server to have a mix of websites that each reference crystaldecisions dlls, where one website references version 11 and the other references version 12?

In otherwords, does BO 11 and 12 (BOXI 3.2) play nice together on the same web server?

I ask because we seem to get an error when we hit one site, then go to the other. only an iis reset will clear up the error.

I'm thinking that the server should only have one version installed, but I'm not sure.

Thank you.