Auto populate Fields based on Tags

I have the Enterprise edition Zendesk, and do not have the ability to:

Automate or auto-populate certain “Ticket Fields” to either appear or make existing fields mandatory.
I am aware I can make it select other categories, but need the Support person to follow some steps – if we can not make that possible, can we at least populate a Macro to appear when these categories are selected (I am aware our support doesn’t just search the bottom and type the Macro).

For Ex:
If they select SmartSheet – they are required to fill out the Team Viewer ID field.
It will be better to make it appear when they select the desired category.

Thank You