The reports that only show AspectCC are possibly the older version (but actually much faster in my opinion). There are two options, if indeed these are the older report files.
The first option is to get a copy of the newer ReportFolio files for SI, which gives you the option of selecting the CallCenter from the picklist that you populate with the corresponding DSN names, i.e. 1000_P, 1001_P, etc. At this point, you will need to set the new picklist file under the report properties, under the prompts tab. AspectCC is probably pulling up from the default picklist that Aspect provides with the reports.
If you have the older version of the reports and choose to use them, you have the option of setting up a different Report Job Server for each Call Center you wish to run against. You simply set the AspectCC DSN to point to the Call Center you wish to run against on each Job Server. Once you've done that, separate each Job Server into it's own Processing Server Group, and select that correct server group under the 'Servers' tab when you set up your reports. It takes a bit longer to set up initially, but I've found the report processing speed to more than make up for this, over the long run. I've used this method to great effect in the past (before we went to Crystal Enterprise).