Thank you all for all your answers so far. So that's my plan so far:
I will host an runaliyze instance. Every employee may use it, but is free to use any other service, as long as it offers a public api. I will create a service which consolidates the data from all sources of the participants to show the statistics of the group competitions.
@homer77 @SkyfaR @SimonWpt @JayVii_de
toot.nx-pod.de is one server in the network