You can exclude a combination but not a specific intersection. EXCLUDE ("F2", "C1", "A1") will exclude F2, C1 and A1 completely.
As Evgeniy.Rasyuk said, you have to use a different way to achieve it.
You may achieve it using a rule file. I haven't tried it but you can give a try
1. create a new text field in rule file which you use to load the data
2. Join all the fields of dimensions related to F2,C1,A1. (remember to ignore this field during dataload
3. use reject on the filed to exclude F2C1A1 to load to your database.
The other way is what you have said to clear the data once it is loaded. Easiest and a simple way