Multisite Calendar: cross site events

Hi,

I have looked around for this plugin and didnt really find a solution.

I have 15 sites on a multisite with individual calendars and programs. However...

From time to time, single events could be interessting for all the sites and sometimes just for a few of them in groups (spanish sites, german sites, dutch sites etc.)

Does anyone know a solution for to this somehow special need ?

Kind regards Peter