Filter contacts based on a custom field to create a segments

Filter contacts based on a custom field to create a segment. Some of our clients import very large contact databases (ex 100,000 contacts). We have received time to time requests from clients/leads who want to create segments based on specific information stored in a custom field.

For example, we are currently handling a case where a Spanish leads with around 80,000 contacts wants to segment them by postal code. Since there are over 550 different postal codes, using tags would be quite complex.

We were wondering if it would be possible to add the option to filter and create contact segments based on a custom field.