Being the Studio Assistant, if people forget to set their "out of office" I have to set it for them. Obviously we don't want to keep a copy of everyone's login details.
Is there a way I can do this through our Google Apps account or something?
Unfortunately it's not possible to set another app-domain user's email to out of office via the admin interface.
There is an API for managing vacation responders, however. But in the Google Apps Marketplace I could only find 1 app that could possibly do what you need it to do and it's a paid app. This is the link to that app
If you have Google Apps for Businesses you can do it. If you are not too familiar with REST interfaces you can use this open source project that has a command line tool for setting the away message of any user in the organization. It is very simple to use:
gam.exe user <user-email> vacation on subject "Away Message Subject" message "Away message body"
Unfortunately the setup of the tool was quite a pain, but well documented. Took me about 20 minutes of creating oauth keys and like.
You have to be an admin of the domain. Of course ...
Use your Apps account to reset their password to "OnlyIdiotsForgetToSetTheirOOOMessage". (or maybe something less inflamatory!)
Log in to their email, using this password, and set the message.
When they come back to the office and cannot log in, sigh plaintively while going into Apps to reset their password again.
Email was never created to have multiple users, it defeats the purpose. The best and only solution is to share login credentials with one another. Although it isn't the best choice security-wise, it is indeed the simplest to implement (assuming the people of this group have a decent memory).
The alternative would be to have all accounts forwarded to one central account that everyone has access to (while still keeping copies on everyone's separate accounts. Redundancy they call it!
If, however, you just so happen to be sysadmin with root access to the email server, .. well, then I'd say you're in the wrong SE site.