I have a sheet of some 2000 rows that runs like this:

```
GROUP PERSON
A Group John Croft
A Group Mike Federer
A Group Billy Placente [ed: NB]
A Group Louise Sheen [ed: NB]
B Group Mitch Balm
B Group Meghan Gore
B Group Elvis Kai
C Group Eric Almont
C Group Billy Placente [ed: NB]
C Group Louise Sheen [ed: NB]
```

I’m looking for a formula that will be able to tell me when two or more people from one group appear **together** within another group (e.g. the highlighted rows above).

Ideally the output would be a third TRUE/FALSE column indicating whether the person in that group/row appears in another group with another member of that first group.

I’m thinking that this might be doable using array formulae but beyond that I’ve no clue.

Thanks!

I’m afraid the best way would be a bit of a work-around, by using a connecting column.

Each cell in the column will contain data about a 2×2 “square” of cells `A2, A3, B2, B3`

(and the consecutive row numbers, of course).

Then we’ll be able to compare every “square” with the other squares.

A possible implementation would be:

```
A B C D
1 Group Person
2 A Mike Mike-Joe TRUE
3 A Joe Joe-Tim FALSE
4 A Tim FALSE
5 B Morty Morty-Rick FALSE
6 B Rick FALSE
7 C George George-Mike FALSE
8 C Mike Mike-Joe TRUE
9 C Joe FALSE
```

Where the formula in `C2`

(and similarly in `C3`

, `C4`

, etc.) would check if the next line contains a person *from the same group* (otherwise it’s left empty):

```
=IF(A2=A3, B2&"-"&B3, "")
```

And the formula in `D2`

(and similarly in `D3`

, `D4`

, etc.) would be:

```
=AND(C2<>"", COUNTIFS(C:C, C2, A:A, "<>"&A2) > 0)
```

Which checks if the corresponding cell in column C isn’t empty **and** if there’s another cell that equals to the corresponding cell in column C, but differs in column A.

Tags: excelexcel