Adjusting the duration of specific slides only

Hi,

I have built an elearning course where I want the user navigation to be restricted as it is a compliance training piece. However there are a couple of slides where the user is more than welcome to click ahead. I know how to individually modify an individual slides navigation. The problem is and let's use slide 1 as an example. This slide is an introduction to the course. It asks participants to have headphones ready, instructs them where to find notes etc. For some reason this slide shows as being 1 minute in duration and participants can't click ahead until the seekbar reaches 1 minute. I would like participants to be able to click ahead this slide (plus a couple of others towards the end) but then have restricted navigation for the remaining slide.

I hope this makes sense?

Cheers

Damian