I wrote a custom collectionlink field and added a string concat function.
Usage:
Copy the modified file to /path/to/cockpit/config/tags/field-collectionlink.tag and add your display field names in brackets. The string replacement is inspired by the set renderer.
{
"link": "persons",
"display": "{first_name} {last_name}"
}
I didn’t test it with "multiple":true. Feel free, to send a pull request, if you find any issues.
If you use such modified files, don’t forget to copy them to remote locations… and if you ask for help on discourse, don’t forget to mention, that your issues might differ from the default behaviour. And, obviously, custom tags won’t receive updates when you update cockpit.