Show % value from one table whilst filtering from another

I have a table called the WorkShift table, it is basically a query table and brings together the totals from other tables. So the Workshift tbale for example will give me the total number of good and scrap parts a machine makes. In the workshift table, I have a calculated column in which it works out the & of scrap parts compares to the amount of good parts said machine makes. Each scrap part that is produced has a fault reason, but that fault reaon is not in the workshift table and the workshift table just bring in numerical totals. The fault reasons are only present in the production table. 

I want to be able to exclude certain reasons. for example, some scrap is planned scrap and i don't want to include this in the %. But onbviously I can't filter out the fault reason in the workshift table because the fault reason doesn't exist in the workshift table, and I am not able to get the fault reason in there because I can't combine several reason under the totals in the workshift machine. So how would I be able to filter the fault reason in the production table but have my value field in my visual display from the workshift table?