Hello nageune
You have to understand that, when you want to load bicycles onto the train yourself, this is a difficult undertaken with 9 bicycles. The train companies transport bicycles only if there were bike spaces left. There is no guarantee that you can ride with the train when having a bicycle. This means, some group member might be left behind and have to take the next train.
Using the train with a bicycle is very popular in Switzerland. On days with great weather, there is not enough capacity on the trains and people with bicycles are often refused.
IC trains require a mandatory bike reservation on some days; for example, for the Brig to Spiez route, you need a reservation on FRI, SAT, SUN days. On other days, bike spaces are available as first come, first served. However, I assure you, you won’t be the only one travelling with a bicycle. Again, there is no guarantee that you can travel all together. You might have to travel on different trains, making your itinerary unreliable.
You should consider the option to rent bikes at the different stations according to your itinerary. Or to send it by luggage services, while they will be delivered in two days counted from the day of check-in.
In my opinion, travelling with a group with bikes on public transport services with self-service loading is impossible, and I must say, working as a train chief, I have never seen it before.
You might have to consider the option to rent a transportation company that is transporting your bicycle from A to B.
Kind regards,
Roland