It depends how seemless you want the process to be?
Are you ok with your audience seeing you move from the looped slides into your main presentation or do you want it to be completely invisible to your audience?

You can setup 2 x custom slide shows and run slides 1-5 as the first custom show and have them loop and then have a second custom slide show with slides 6 onwards and activate that once you are finished with the initial slides looping.