Completely do-able, Tadd.
Start the easy way: create your 2 data sources independently. Then, in a new worksheet, go to the menu item "Data", then "Edit relationships".
It's very likely that ONE of those 2 data sources has the complete list of customer ID's. Make that one Primary, and connect the 2nd data source as Secondary, using the Customer ID field.
"OK" out of those dialogs, and go back to your worksheet. You can now use fields from both sources in one viz. Whichever source your pick your first field from when you build the viz BECOMES THE PRIMARY SOURCE - you'll see a blue check mark show up when you drag a field into the view. In what is now the secondary source, you'll see a little chain link icon next to the Customer ID field. It will be grey: click on it and it turns orange, which means your data sources are now BLENDED for that specific worksheet. (That data source will also get an orange check mark next to it.)
Now play around - you'll run into some funny behavior from time to time, but that should get you started. Come back and ask more questions when that happens!