Issues with auto updating App Store - OSX Ive got 5 or 6 Macs that I'm responsible for the security of. One of the things I want to do is keep all the macs on the latest security patch for their respective OS. 

We have a mixture of 10.10.5 and 10.11.x OS across the different machines, some of the machines, need to be on 10.10.x as some mission critical software we use on them only runs on 10.10.x

I noticed there is an auto update feature for the OSX App store, but I'm concerned of two things : 


It will auto update the OS to Sierra or what ever is latest when it is auto updating (I only want to update to the latest version of my current OS to encompass security patches etc.)
If a user choses to restart the machine in the middle of the day it will start trying to install software and take 30 mins to to install where as the user was only hoping to do a quick restart and get back to work


Is there a way around either of these points?
As far as I know and I'm using a MacBook Pro too, when you set automatic update, it will automatically download and install update.

However, for big upgrade, it always ask you do to it, such as upgrade from the current version to Sierra.