It is possible to assign multiple users or a group of users if you have previously added one or more tags to the colleagues of your network. You can do that by simply going into the "Colleagues" section and then, on the card of the user you would like to tag, select the tags you wish to assign to him. For example, you can tag them by function (electromechanic, boilermaker, etc.) or by team (night shift, weekend team, etc.).
If you have done that already, then you just need to select, during the task's creation, the "Add a user group" button. From there you can select the desired tag or tags and all the users affected will be automatically assigned to the task.