It is very simple to create multiple notifications for single application (e.g. two notifications for WhatsApp - one for your Mom and the other for your Boss), each with different patterns and/or conditions:
Create an application notification
(optional) Set content filter for the new notification (e.g. Mom)
In the "Filters" section, below the "Content Filter" option, tap on "Duplicate Notification"
Enter filter for the new notification or leave it empty to create notification without content filter. Enter for example "Boss"
Click on "Duplicate" - you're now editing an notification with this new filter ("Boss"), feel free to adjusts the pattern and/or conditions to your needs
Repeat steps 3, 4 and 5 as many times as you want
If you want to learn more about the notification duplication and about the way how filter priorities are designed in Mi Band Tools, please make sure to read the in-app dialog regarding notification duplications. You can find it when you tap on "Duplicate Notification" - "More Info". You'll find more useful information there and you will learn how fallback (empty) notification filters works with other filters and many more useful information.