Send welcome email from different email account

Hi

I want to setup email like:

I want welcome email to be send from different email account.
I do not want to send welcome email to my customer from default outgoing email instead from different company email account as I have multi company in my setup. how to setup this?

I want all my HR related things email from HR specified email not from default outgoing. How to do this?
Same goes with projects.

what if my sales team wants to send email to customer that belongs to company B and my sales person belongs to company A, but he wants to send email to customer from company B email how to function this?

Moreover, is there a possibility that my production team should not be able to see whole company email list while assigning a project. It should be like user A belongs to production team must be able to assign a project to a production team user only not sales team nor salesperson email should show in list.

Like in attached picture, it showed all email users however it should be only few. any guide here

@frappe