Complex issue... Need help, IF THEN, etc...

Hey all, here is the issue:

Overall though I need a formula that calculates the average of the column K value, only if there is an "X" entered in column C for each category (QOD, NPF, QA, AHT, CSAT & FCR) individually into the totals section at the top of the spreadsheet.

For example, in the "Total Average" Column located in F3, taking for example QA, the cell to the right (F5) should only return the average of the QA category for Agent Two and Agent Three, because Agent One was not trained on QA.

If anyone can help me with this it will be greatly appreciated.

The data is as follows:

Agent Trainer Trained Category Week 1 Week 2 Week 3 Week 4 % Change
Agent one Jeff Rodgers QOD 25.00% 50.00% 75.00% 100.00% 75.00%
Agent one Jeff Rodgers NPF 50.00% 50.00% 80.00% 80.00% 37.50%
Agent one Jeff Rodgers QA 50.00% 50.00% 80.00% 80.00% 37.50%
Agent one Jeff Rodgers X AHT 50.00% 50.00% 80.00% 80.00% 37.50%
Agent one Jeff Rodgers CSAT 50.00% 50.00% 80.00% 80.00% 37.50%
Agent one Jeff Rodgers FCR 50.00% 50.00% 80.00% 80.00% 37.50%
Agent Two Jeff Rodgers X QOD 100.00% 100.00% 90.00% 90.00% -11.11%
Agent Two Jeff Rodgers NPF 100.00% 100.00% 90.00% 90.00% -11.11%
Agent Two Jeff Rodgers X QA 100.00% 100.00% 90.00% 90.00% -11.11%
Agent Two Jeff Rodgers AHT 100.00% 100.00% 90.00% 90.00% -11.11%
Agent Two Jeff Rodgers X CSAT 100.00% 100.00% 90.00% 90.00% -11.11%
Agent Two Jeff Rodgers FCR 100.00% 100.00% 90.00% 90.00% -11.11%
Agent Three Jeff Rodgers X QOD 100.00% 100.00% 90.00% 90.00% -11.11%
Agent Three Jeff Rodgers NPF 100.00% 100.00% 90.00% 90.00% -11.11%
Agent Three Jeff Rodgers X QA 100.00% 100.00% 90.00% 90.00% -11.11%
Agent Three Jeff Rodgers AHT 100.00% 100.00% 90.00% 90.00% -11.11%
Agent Three Jeff Rodgers X CSAT 100.00% 100.00% 90.00% 90.00% -11.11%
Agent Three Jeff Rodgers FCR 100.00% 100.00% 90.00% 90.00% -11.11%