Resource management

Perhaps management has a responsibility to facilitate availability, and to encourage skilled people to self-organize into teams. I'd suggest that the first step towards doing so might be to avoid contextualizing these professionals as resources.

@Ian Mitchell is correct.  

I will add that as Scrum Master you should help remove the impediment if the team asks for the help.  But if I were in your position, I would suggest that the Developers bring it up with their manager and let all of them be the one to navigate the corporate process.  The Developers should work with their Manager at coming to a solution that makes sense and is executable. 

I'd suggest that the first step towards doing so might be to avoid contextualizing these professionals as resources

Amen 

When there are several teams for a product, according to Scrum, how should the people be distributed in teams? The management decides? The developers choose? Where could I find this information? Thanks

The Scrum Guide says that adaptation becomes more difficult when the people involved are not empowered or self-managing. When there are several teams working on the same product, self-management is therefore the way to go.

Bear in mind that this is a skill to be acquired, and a Scrum Master will coach team members to self-manage effectively.

It can be helpful to:

• create a bounded environment (e.g. a timebox) within which people can take action,
• give them a clear goal (e.g. each team ought to be able to create Done features) and
• provide clear rules (e.g. a maximum of roughly 10 members).