Team, team work, Sprint, Sprint Goal

Hello everyone,

Here is what I observe in the team I work for as a Scrum Master:

At Sprint Planning, capacity discussion is mainly directed by defining who are the people who are going to work on developing a given "feature" during that Sprint (maybe a way to ensure everyone is kept busy?), and every developer is going to develop a different one because, according to the developers, "there is no way to work together on the same feature", and perhaps no way to split the feature in tasks which can be maybe done in parallel (one "logically" requires the end of the other).

Implications:

- having each person a different topic and knowledge

- it is not easy to design a Sprint Goal for the whole team

- team collaboration is, IMHO, limited 

I understand that the Developers are supposed to self-organize about their way to work together, but I fear they are not doing the "the best way" and they are resilient to try to question or change it.

How can we be sure there are no ways?

Focusing one retrospective on this topic risks to result in short-cut discussions like "We can't do that, that's it".

I think I need your help to see how and if this situation should be handled.