User Device Access

So I have created multiple user accounts. Is there an easy way to add multiple devices for the group or like a whole subnet? Also it asks for an email for that account. Does that mean they will get notifications too?

i would also like the abolity to add a entire subnet or two to the normal user grant access list… ?

We have different groups like security, networking, and servers. And would like the security group to only get emails on firewalls ect.