The only way to do this would be to add all folders other than
OfficeImportants to the exclusion list in the options pane of the Time Machine section of System Preferences.
For instance, if
OfficeImportants was in
~/Documents/OfficeImportants, you would need to add the following to the exclusion list:
As you can see, that's a lot of exclusions. What's more, you'd need to keep adding exclusions for any folders you subsequently create in
/Users (i.e. on user creation), your home folder and
~/Documents. Time Machine is set up to assume you want to back up everything, with only a few exclusions. While it's very good at that, using it for anything else can be tortuous.
If you want to backup a specific folder, you're probably better off using a different program. SuperDuper used to be the go to backup program for Macs, and is more flexible than Time Machine. If you don't want to pay for SuperDuper, rsync (which should already be installed) can be prodded into behaving very like Time Machine, with the exception of the restore interface and with complete choice over what you back up.
On a related note, if you're not using Time Machine to back up everything, I hope you're using something else to. Hard drive failures don't just happen to other people.