How do I select input signals from a Bus one after another for a For-Iterator in Simulink?

I want to select input signals from a bus one after another e.g. to sum them in a For-Iterator. How do I implement this in Simulink only by using blocks from the library?

How can I select bus signals in a dynamic way in Simulink? Is there a way like a selector with input-vectors to select the specific signal?

Thank you!