Limit the Users that appear in a User List field?

[Deleted user]

We have users that exist only for the purpose of notification. For instance, that user gets sent an email as a post function in a specific workflow. 

However, we are now seeing that user in the list of users for custom fields of type "User Picker". They can not be assigned issues in the "Assignee" field, but they CAN be set as an assignee if they are selected from the custom user picker field. 

Does anyone have any suggestions for dealing with this? According to the directions for configuring a custom field (https://confluence.atlassian.com/adminjiraserver073/configuring-a-custom-field-861253383.html)

it's supposed to be possible to apply "User Filtering", but I don't see that working in our Jira version 7.13.

[Deleted user · Accepted solution]

I may have answered my own question. It appears this only applies to the Single User user picker field. It's not a configurable option for the Multi User user picker field.

[Deleted user]

The multi-user field doesn't have this option, as discussed here:

https://community.atlassian.com/t5/Jira-questions/Limit-Multi-User-Picker-field/qaq-p/923953