Setting all visible fields except for a few, to read-only. But only for a specific group

[Tylee Gooderham]

We have a need to prevent members from a specific group from editing any fields on an issue, except for a few custom ones.

We are using JIRA server and have ScriptRunner in place.

My initial thinking was, enumerating all the fields that are visible on the current issue and setting them all to read-only except for those they are allowed to edit, IF the current user belongs to said group. 

Assuming I'd be using the ScriptRunner Behaviour, I was trying to figure out the Initializer Script code to run on-load, to set all fields to read-only. Then... i'll configure the wizard to make the 5 or so fields editable afterward

I'm not finding code that will set all fields (system + custom) to read-only. Does someone have a way of doing this?

Also, is there a better way to achieve this?

Thanks much,

Ty