Perhaps you could break them into teams. One strong reader, a medium reader or two, and a weak reader. Have the strong reader lead out, and the others keep up as they can. Read a little, break and discuss what was read. Do this for five to ten minutes, and then go back, and re-read the section, with the poor readers reading the section they have already discussed, and gestured with perhaps, and the strong reader there to give prompts if the weak readers trip over words.
If you like it, I would let them try it a couple of times to get used to the process before they do it at the observation. If you do not like this approach, hopefully I have given you an idea as you read it. Hope this helped.