First I have no idea about Active Directory.
You mean share1 be accessible to IT, share2 to finance, and share3 to sales. But certain non-members of finance should have same rights as their members to share 2, right?
Why don't you simply add those users of "management" to the finance group using usermod -a -G command?
Or you can create another group with all users of finance group, as well as the management team members and chgrp to that?
Or is it I am totally misunderstanding your question.