Germany has monthly local public transport passes for 49€ for all local public transport including regional trains. So if you wanted to go that kind of distance, you propbaly buy that instead and use public transport for some trips in the city or for some other trip. For groups some states have state passes, which can be very cheap as well. Lower Saxony for example has the Niedersachsenticket, which is 25€ for the first person, another 6€ for the next and then 5€ for each of the next three people. That works for a day after 9am for all regional public transport in the state. So you could get everybody within a normal sized car on a similar distance for 46€.
In other words, I am sorry, but public transport in the Netherlands is more expensive then in Germany. At least it is on time thou.