priortizing images in random playback

[newsposter]

Seems that this request is counter-intuative, but bear with me.

Say I've got 1000 images for a corporate event. These are for 'background noise' during meals, the hotel lobby, etc. There are approx 10-25 of those images, CEO and Exec Board photos, program listings, company logos, etc, that should really come up every 5 minutes or so, certainly a lot more often than they would in a 1000 image random rotation.

I know the obvious 'cheat' of putting in an image multiple times with different names. I use it all the time with mostly unsat results........

Would like to have a much more controllable option. Every xx minutes or ever xx random images show this specific image or group of images. Repeat as desired.

Alternatively, how about some kind of chapter-style construct wherein there could be chapter-heading images and the have the chapter body (image collection) be shown at random? Move on the the next chapter or mix up the chapters at 'random'.

???