Hi Kip,
In the basic CheckBook (green pen icon), the ability to combine data from multiple Accounts isn't there but with Pro (blue pen), it's possible. Basically, the Pro version combines data from all of your Accounts when the All Accounts option is selected. If you're on basic, here's where you can try out Pro:
http://www.splasm.com/checkbookpro/index.htmlSupposing you have more than those two Accounts you want to see combined, you could lock the other Accounts with passwords and that would hide the information from the All Accounts view.