You'll need to use ssh or 'Remote Desktop' from Apple to apply these updates to the clients. A pre-requistite for this, that you may want to go around and setup on all your OSX clients once, anyway, is that in the Sharing preferences, ssh aka in OSX gui-land "remote management," and possibly also "screen-sharing" is enabled.
The installations on your OSX clients will fall back on the settings in System Preferences -> App Store (if needed see the imagenear the bottom of this answer), and if all of the options were "checked," the clients would have probably already upgraded themselves to El Capitain. As far as I know these updates, if not explicitly allowed, are applied only on an admin login, or on a restart (e.g. a scheduled restart from Energy Settings -> Advanced).
So assuming that you have the settings in System Preferences set to (not) allow automatic updates, or to only allow security updates, how I frequently use them on my clients, there will not be any other semi-automated option.
Apple does offer an Application called Remote Desktop, which provides a bit more tools; it is really fun, but to be honest, I've used a lot of time trying to use it, or find ways to look like more of a rock star by doing command-line installations in OSX, but in many of my use-cases, the software requires some type of dialogues that can't be scripted out or included as an argument to
The closest feature I know of from the official Apple tools so-to-speak, is to use
Remote Desktop or another application where you can do
ssh into multiple systems at once (e.g. Puppet) and then
sudo softwareupdate -i 'OS X El Capitan Update-10.11.1'
or apply the exact update that you wish to use
you can first use
softwareupdate -l (--list) to see which update it is that you would like to apply
If you don't have as much OSX experience as I've assumed, we can expand the answer or comment back and forth until we've got you covered.
It should work well for you to use Bash, as described above, since you are looking into the one, specific udpate, after you find out what it's specific name is. I've called it "OS X El Capitan Update-10.11.1" above.