Complicated Sumif or Index Problem - need a pure genius for us

Hi, all
Straight to the problem.
To give you some background, We will work on this within a single workbook (no pulling from other workbooks). There are about 13 worksheets(tabs). First one is a roll-up sheet and second thru last one is by monthly data( 1-12).
From the 2nd tab to the last tab, formats are same, the dollar values that I need to pull from are in the same column (column O).
In every worksheets, there are list of three letter code such as LDD and LAI to distinguish different names in column B).
Problem is they are duplicate of three digit codes with different dollar value.
Ex)
Column B Column O
LDD ----------$200
LDD ----------$340
LAI -----------$100
The duplicate codes are bind together like above. Not like
LDD
LAI
LDD

So this is what I want to acheive.
I want to find the dollar value of the relevant code from each tab and get a sum of the value in my roll up tab, very first tab.
So I could be pulling 2 LDD dollar value from tab2 and 4 LDD dollar value from tab3, 1 LDD dollar value from tab4 and etc...
I was using Index Match but it limites to pick only one excluding duplicate code named values.
Also, I tried sumifs to pull data and made it almost all manual work.. (no point at this time).
If anyone could help, I'd greatly appreciate it!

Let me know if you have any questions,
Thank you in advance.

See if this will work for you. I Tried attaching a workbook, but site is acting funny right now.

Create a named range listing all the sheets you want to use. I used sheet.

Then a formula like this in cell B1 and drag down will work.

Formula:

Please Login or Register  to view this content.

Your post does not comply with Rule 1 of our Forum RULES. Your post title should accurately and concisely describe your problem, not your anticipated solution.

Use terms appropriate to a Google search. Poor thread titles, like Please Help, Urgent, Need Help, Formula Problem, Code Problem, and Need Advice will be addressed according to the OP's experience in the forum: If you have less than 10 posts, expect (and respond to) a request to change your thread title. If you have 10 or more posts, expect your post to be locked, so you can start a new thread with an appropriate title.

To change a Title go to your first post, click EDIT then Go Advanced and change your title, if 2 days have passed ask a moderator to do it for you.

(This thread should receive no further responses until this moderation request is fulfilled, as per Forum Rule 7)