Bitrix api. How to optimize a script (similar to searching for duplicates in a company)?

Question

1C-Bitrix

The problem is that I need to actually take all crm companies and compare whether the user field matches.
Matched send to the US.
Now I see it this way. getlist of all companies. Go through each and again filter all companies.
It just seems to me that this is somewhat wrong and the agent will load.
Are there smarter options?

Answer 1

Group all records by this field, displaying in the results only those with count > 1;
Here is a selection of all the companies you
need. And then, pass these companies to the RS according to the field values ​​from the previous request