SUM if conditions are met over multiple worksheets
 

I am trying to get the sum of all costs in my work book that correspond to a
certain reason.

I have a summary page with the follwing list:
Total $ Amount
Architect Design Issues $0.00
Owner Request $0.00
Construction Deficiency $0.00
Errors & Omissions $0.00
CM / Scope Issues $0.00
DSA / Code Requirements$0.00
Unforeseen Conditions $0.00
Value Engineering $0.00
$-

I have a separate work sheet for all contracts. Each work sheet has a list
of changes to the contract. The sheets have separate columns for
description, cost and reason. The reason code can be selected from a list.
I want the summary page to total all costs with associated reason.

For example I want it to sum the costs of all changes that have a reason
code of "Architect Design Issues"