How would you tackle a large corporate intranet's team member / manager / head of department structure

Hi guys.

Any help, tips and advice would be greatly appreciated!

The first goal is to have a full company hirerarchy, so we can build an "attendance" module that let's a manager complete their team's attendance online. For this to work, Drupal needs to know what people are in a managers team. Rather than let users select who their manager is, we would prefer for a manager to select what people are in their team. Team members won't have permission to remove them self from a team, it has to be a manager that "pulls" a person to their team, removing any previous managers that have them as a team member.

I've had a look at the user_relationship module but it doesn't seem finished enough to use on a live site.