The DVD Specs were written over 15 years ago, when microprocessors were very weak and had limited memory addressing capabilities. If you break this rule, your DVD will not play.
So your only choice is to use buttons over video in the VTS domain, which Encore does not support. So you will need to find a professional or prosumer-level authoring application. On Windows, there is Scenarist and perhaps others.
On Macintosh it can be done with DVD Studio Pro. here is an explanation from the DVD Studio Pro 4 User Manual: