A new Custom Field able to display users selected for a "Role" in the Project

I have followed an issue (JRA-5493) calling for the possibility to have "watchers" selected while creating an issue.

I have been suggested to create a new Role, "Default Watchers" and, playing with Notification Scheme, instruct JIRA to notify at issue creation.

Now, having implemented somhting which is "similar" to the "Watchers", I would like to show, in the issue details window, that there is a list of users included in the Default Watchers Role.

Would it be possibile then,, as you did recenbtly for Watchers and Voters, with a plugin, to create a new Custom Fiels able to show, maybe choosing which Role, the list of Users ?