COS Feature "Group calendar"/merged calendars

[catnipper]

I am currently looking at possibilities how to provide users merged corporate calendars such as consolidated department or corporate schedules.

During my research I did find the COS Feature "Group calendar". Until now, I understood from the documentation (ony 2 lines address this topic, p. 141 Adminstrator's giude) the only functionality this setting provides is the ability to share a (re-)source to members of distribution lists instead of to individuals only.

1. Is that right - anybody has other experiences?
2. Anybody found an easy to implement 3rd party solution to merge individual calendars into one based on distribution lists or even multiple nested groups (excluding private appointments)?

Instead of writing something new from scratch, I thought of having a look at bedework...
Anyone else did such a thing before and found a suiteable solution?