The Scenario
You are a list manager at a media company. You run a newsletter list and a promotional list in Benchmark Email, two of your six total lists. The newsletter list has 14,000 subscribers. The promotional list has 9,000. You are planning a re-engagement campaign that should only go to newsletter-only subscribers, people who never opted into promotions.
To build the right audience, you need to know who appears in both lists. Those people get suppressed. Everyone else in the newsletter list gets the campaign.
The only tool you have is a Google Sheet.
The slow version:
- Export newsletter list as CSV, paste emails into column A of the sheet
- Export promotional list as CSV, paste emails into column B
- Write a COUNTIF or VLOOKUP to find emails that appear in both columns
- Filter to the overlaps, tag them for suppression
- Hope you did not miss anyone
- The sheet has 14,000 rows and VLOOKUP is running slowly and you are questioning all your choices.
The fast version is one prompt.
The Easy Way: One Prompt in SheetXAI
SheetXAI is an AI agent inside your spreadsheet that pulls both contact lists from Benchmark Email and runs the overlap analysis for you, without a CSV export or a formula in sight.
Open the SheetXAI sidebar and type:
Compare contacts across Benchmark Email list IDs in column A of my sheet. Find every email address that appears in more than one list. Write the overlapping emails and their list memberships into a new tab called Overlaps — one row per shared contact, with their email, name, and a comma-separated list of which lists they appear in.
SheetXAI pulls the contacts from all list IDs in column A, identifies the overlaps, and writes the results into the Overlaps tab. You get a clean suppression list without touching a CSV.
What You Get
A completed overlap analysis in the Overlaps tab:
- Email address — one row per contact who appears in more than one list
- Name — first and last name from Benchmark Email
- Lists column — comma-separated list of which list IDs each contact belongs to
- Row count — the total tells you exactly how many contacts to suppress before sending
The suppression list is ready to use. Download it as a CSV or use it directly in SheetXAI to suppress those contacts from your Benchmark Email campaign audience.
What If the Data Is Not Quite Ready
Cross-list analysis has a way of revealing more questions than it answers.
When you need to find contacts exclusive to one list
You do not just want the overlaps. You want the newsletter-only subscribers, the people who never opted into promotions.
Pull all contacts from Benchmark Email list IDs in column A. Write contacts who appear only in list ID 1122 (newsletter) and not in list ID 3344 (promotions) into a tab called Newsletter Only. Write the overlapping contacts into a tab called Overlaps. One row per contact in each tab.
When the contact records have slightly different email formatting across lists
One list has "Jane@example.com" and the other has "jane@example.com." They should be treated as the same person.
Pull contacts from all Benchmark Email list IDs in column A. Before comparing, normalize all email addresses to lowercase. Write overlapping contacts (based on normalized email) into the Overlaps tab. Write the original casing from each list into separate columns for reference.
When you need to compare all six lists at once, not just two
The newsletter and promotional lists are just the start. You want a full picture of how all six lists overlap with each other.
Pull contacts from all Benchmark Email list IDs in column A. For each unique email, write a row into the All Contacts tab showing the email, name, and a "1" or "0" in separate columns for each list ID — one column per list. That gives me a presence matrix I can filter any direction.
When you want the overlap analysis plus a campaign-ready suppression file in one step
The analysis is useful, but what you actually need is the suppression file formatted for upload and the clean send list in the same operation.
Pull contacts from Benchmark Email list IDs 1122 (newsletter) and 3344 (promotions). Write contacts who appear in both lists into the Suppression tab — just email addresses, one per row, no header. Write contacts who appear only in list 1122 into the Send List tab with email, first name, and last name. That is the re-engagement campaign audience.
The pattern: describe the output you actually need — suppression file and send list — and let SheetXAI build both from the same API calls.
Try It
Get the 7-day free trial of SheetXAI and open a sheet with Benchmark Email list IDs in column A, then ask SheetXAI to run the cross-list overlap analysis. The Benchmark Email integration is included in every SheetXAI plan. See also how to export all contacts for deduplication or the Benchmark Email in Google Sheets overview.