ScriptRunner: Possible to group issues in a project by assignee and capture number assigned?

[Craeg Strong]

HELP- Some of my team members are taking on too much work!  The subject matter experts are getting pulled in 1000 directions and it is causing delays

I am trying to use Script Runner to implement a basic per-person WIP limit capability for the project.

The idea is to have a quick filter button that automatically identifies cards for users that have more than 3 cards assigned to them.   

Here is some pseudocode in SQL to illustrate the point:

    SELECT ID, COUNT(*) c

    FROM issues 

    GROUP BY assignee

    HAVING project = "my project" and c > 3

I am pretty sure this is doable in Script runner, and therefore should be possible to put into a quick filter.  

Note that what I actually want is a wee bit more complex than this, since I actually want to combine my custom "collaborators" field with "assignees" to get the total workload.  The issue is not that my SMEs have actual work assigned directly to them, it is that they are needed by too many people at the same time to collaborate.   This would be a straightforward extension if we can get the basic script working though, so I don't want to get ahead of myself...

I noticed some discussions about not having a per-person WIP limit feature in Jira.  I realize this is a hack, but it would be way better than nothing if it could be made to work.

Thoughts?   Would this be useful to others?  Do you have a different way to help solve this problem?  Either way, I would love to hear it.