Form Tab Order for navigating a form's input fields

Is there a way to override the default tabindex behavior of buttons?

I have a use-case where I want the user to tab between text-boxes, and to ‘skip’ the buttons on the form. So I’d like to set the tabindex of my buttons to -1.

It seems that TabIndex is not settable by CSS so I am stumped on how to use Roles here. Any other ideas?

I messed around with a javascript function using the guidance here, but got nowhere.