Sort of, but not specifically with OneCare.
Well, with OneCare, when you create the backup plan, it will backup on the schedule you set and backup the data you specify (by file type) and to the location you choose. If you then modify the plan to backup different data to a different location, the original plan is gone and the new plan takes effect. So, you can't have two plans on the PC at one time.
That means that you can choose to backup all data in one plan to a single destination. This might include your personal and work files or just one type, based on exclusions of folders or specific files from the plan.
Then, to backup to the other external drive, I'd suggest using a free utility, SyncToy to sync folders of your choosing to the other external drive. SyncToy is unsupported, but it works quite well - http://www.microsoft.com/downloads/details.aspx?FamilyID=e0fc1154-c975-4814-9649-cce41af06eb7&DisplayLang=en
-steve
