Disable scrolling between set points

Does anyone know of a way I can disable scrolling between specific points?

I want people to use the header buttons to take them to each section of content.
What I don’t want them to be able to do is scroll up and down in order to see the sections of content.

I appreciate this seems a bit odd but there are reasons for this (long story)

I’ve created a quick mockup for this, links below.

Presumably I’ll need custom code on the ‘previous’ / ‘next’ buttons also?

Thanks in advance.

Here is my site Read-Only: LINK

Published link: LINK2