The limitations of the Teamwork module are getting me down.

I want to 'publish' a list of tasks to my support department team, but not to
all of support team! And I don't want them to be able to delete those task!
Is it possible to alter the code for the Teamwork module, such that my 'public' tasks are only visible to other staff members who belong to at least one of the departments to which I also belong?
How might I also remove the ability of a staff member who can see my public tasks, to actually edit/delete them?
Has anyone dabbled in these matters? I would appreciate your willingness to share a tip or two.