Storing and using same credentials for multiple servers

Hi
I'm having trouble understanding credentials, but am sure this is really simple...
We have multiple servers that all use the same username/password/domain, and all I want to do is store this information somewhere so when I go to log in to one of these servers it automatically logs in.
Everything I've tried still brings up the RDM Credentials Dialog box when I double click the server. I've tried putting the credentials in Root settings, as well as trying to use the embedded Keepass plugin, always with the same result.
It works fine if I set the username and password for the individual server (in properties), but as there are over 20 of these, every time my password changes I have to update each of them individually which is a right pain in the arse!
I think I'm confusing the purpose of the software, which looks like it might be for assigning extra log-ins to users from an administrator's point of view? I'm not an administrator, just a user who has to access 20+ servers regularly with the same credentials.
And I have tried reading the manual, but a search for the word 'credentials' brings up 700+ results and so far I haven't found the answer...
Please help!