YES, you can notify a task to multiple users.

1. Log in to your Orangescrum account using your credentials.
2. Navigate to Task Detail Page from the left menu.
3. Click on the particular task you want to notify.
4. Select the resources to whom you want to notify the task & Click ‘Post Comment’ (Refer Image 1)

(Image-1)

Note: You can’t assign tasks to multiple users. However, you can notify and collaborate the task with multiple users, so that they can reply or comment on the task.