Hello, @JogoVogo. Instructions on how to create an additional SSH account you can find here. Security-wise it is best to consider the chrooted option. I hope that helps.
Thanks for the clarification. At this point, there is no option to create multiple SSH accounts for single subscription. There's an existing UserVoice request and I would like to encourage you to vote it for it. The more popular a request becomes, the more likely it will be to be considered for implementation.