Ability to configure scope of selection for custom "users field"

What is the challenge?

Based on our use case, we need the ability to configure the scope of selection for the custom "users field"

What is the impact?

Not able to configure the scope of selection.

Describe your idea

Need ability to configure the scope of selection in advance settings of the users custom field based on the use case.

1. Can only select users who have access to the current workspace (such as the default "assigned to" field)

2. Can select users who have access to any workspaces (this is the current setup for the custom field)

3. Can select any users in the aha account. (some users had registered to our aha account, but they are not selectable when they do not have access to any workspace. This setup is needed when the field is integrated with other app such as Jira)