I'm not sure if this is even possible so here goes:
I have a calendar list. After creation of the list I will add a choice field to the list in an event receiver where the choices will be the email addresses of the users in a permission group of the site. Here is my quandary, I need a way to remove/add addresses when the membership of the group changes. I was initially thinking a workflow but not sure how to trigger it, the only way might be to manually trigger the workflow. There may be a better way than using workflows. Any suggestions on how to approach this?