[Google Sheets] How to index/match multiple criteria across multiple sheets [data in same order]

[theexcelcrowd]

I have data from different campaigns in separate sheets [per market]. Actual data is five sheets but in the dummy data, I've only worked with two sheets. In a summary sheet, I want to be able to find the correct value for Sessions in column I of 'Email Sends' sheet. This should check for the month + market name [defined here as GA-1, GA-2] and then return the value based on the correct sheet. How can I accomplish this?
Thanks.
https://docs.google.com/spreadsheets/d/1o3Bwx7IHpgfi0xJdjbLx7wvC2AZhqdCOL4h-sKrLDYI/edit#gid=594963682

 

[Johnny C]

This should be in the questions forum.
If you haven't had an answer from elsewhere I think SUMPRODUCT array form is the way to go, with a dynamic range with the names of the sheets in.

 

[Joe4]

This should be in the questions forum.

I have moved it to this particular forum ("General Excel Discussion & Other Questions" forum) because it is a Google Sheets question (see thread title).
"Google Sheets" questions should be posted here, and not in the "Excel Questions" forum.

 

[Johnny C]

Sorry Joe I didn't read the title
In which case my suggestion is probably worthless lol