Hello and thank you for contacting the Toolset support.
I believe that you are looking to group the results by the value of the custom field. That's not available within the Toolset features. You will need to build a custom shortcode for that. Check this tutorial where we try to group results by year and month, you can produce a similar shortcode where you group your results by that custom field, and where you display it once without duplication on each post of the results. https://toolset.com/2013/10/how-to-group-views-results-by-year-and-month/
The trick is to sort the results by that custom field.
I hope this helps. Let me know if you have any questions.
This ticket is now closed. If you're a WPML client and need related help, please open a new support ticket.