How to split one big list into segments that each get their own email

One email to a whole list sounds like it was written for nobody. Group people by shared situation and write once per group.

Article · 3 min read · Updated October 6, 2026

Send one email to a list of 5,000 people and it reads as if it was written for nobody in particular. A segment fixes that. It is a group of people in the same situation, so one short message can speak to all of them.

You don't need dozens of segments. Three to five is enough to see which kind of buyer replies.

What makes a good segment

A good segment passes one test. Can you write the first sentence of the email so that it is true for every person in the group? If not, the group is too mixed.

Too loose	Better	Why it works
All marketing leaders	Marketing leaders at software companies with 11 to 50 employees	Same size, so the same team and budget problems
Everyone in finance	Heads of finance at companies with 101 to 250 employees	They run the same month-end process, just with more people
Every restaurant owner	Owners of restaurants in one city	You can mention the city, and the first line is true for all of them

Four ways to cut a list

Seniority. An owner decides alone. A manager has to convince someone. They need different emails.
Company size. A 10-person team and a 400-person team have different problems, even with the same job title.
What the company does. Industry, services and keywords tell you what they sell, which shapes what they worry about.
Place. A country or city lets you mention something local, or send at the right time of day.

A worked example

Say you sell payroll software to small businesses. The offer is the same for everyone. Only the opening idea changes.

Segment A: owners of tiny companies

Who: Founders and owners
Company size: 1 to 10 employees
Opening idea: You probably run payroll yourself, late on a Sunday

Segment B: finance leads in growing teams

Who: Heads of finance and controllers
Company size: 21 to 100 employees
Opening idea: Payroll takes your team days every month

Segment C: HR leaders in larger teams

Who: Heads of HR and people operations
Company size: 101 to 250 employees
Opening idea: Every new hire adds more admin

How big should a segment be

Start with 200 to 500 people per segment. That is small enough to write for and big enough to show a pattern in replies. If a segment has fewer than 100 people, merge it with its nearest neighbour. If it has more than 1,000, split it again.

Build one saved search per segment

Build the first search with job titles and company size. How to build a prospect list walks through it.
Check the total at the top of the results. Searching is free, so you can test as many cuts as you like.
Click Save and name the search after the segment, like “Payroll - owners 1 to 10”.
Change one filter, such as Employee Headcount, and use Save as new for the next segment.

The Save button at the top of the filters

Tip: Export each segment on its own, or add a segment column if you combine them. You'll need it to see which group replied.

Common mistakes

Too many segments at once. You can't write well for ten groups. Start with three.
Segments that only differ by name. If the email would be the same, it's one segment.
Guessing the pain. Cut by facts you can filter on, then test the idea in the email.

What to do next

Put each segment into a sheet your sending tool can read. See the columns a send-ready list needs.