Hello ZRH340de
We are happy to read that you will visit Switzerland again. Welcome back then!
Yes, this is definitely possible, the Railjet is operated by SBB on the Swiss stretch. You simply have to hold the return tickets to Buchs SG or Chur at the time when you check-in the bicycles. And, there is free storage at the station of delivery for four days.
Let us know if you have got more questions.
Kind regards,
Roland