3 tier model support

[hikinggrass]

Describe your changes

Issue ticket number and link

Checklist before requesting a review

• [x] I have performed a self-review of my code
• [ ] I have made corresponding changes to the documentation
• [x] I read the contribution documentation and made sure that my changes meet its requirements

[hikinggrass]

(this was just an example of possible usage, see #764 for real usage)