Filtering the Users popup based on Role membership

Hey all,

Using the Users select popup in a Safeguarding custom module, for a specific field - Safeguarding Lead, I would like to be able to only return users who are in the role Senior Keyworker. I’ve found some articles listed below relating to setting the Initial_Filter or setting a custom WhereStatement but I think these relate to filtering based on a field in the form, rather than a field which isn’t present (I may have misunderstood that though).

I think what I want to do is set a custom SQL field for the users popup on that Safeguarding Lead field to include a join to the acl_roles_users table where role_id = [id of Senior Keyworker role] but I’m not sure the correct approach for this as the users popup should behave as ‘normal’ when used in other places, say for the Assigned To field for example.

Any help is appreciated as always, thanks!