Doing an automatic conversion with Photomatix, Photoshop etc. is not the only way to blend multiple exposures in order to extend the dynamic range as as you've found it can be very difficult if you have moving subjects.

A simple way of achiveing HDR effects is to simply layer the images in photoshop and mask the relevant parts of each image. e.g. take the shadow area from one image, take the people from another and take the sky from a third image. This works very well if there's a clear boundary between areas of different brightness. Feathering the edges of each mask makes hides the transitions. If the areas where there is movement don't cross any transitions then it's not a problem.

Another advantage of this method is that it doesn't create and HDR artifacts, such as halos, so produces a more natural looking image. Also it doesn't require any speicial software as layer masking can be done with any competant photo editing program.

Here's an example from a few years ago when I climbed Mount Snowdon with some friends. Coming down there wasn't a lot of time to hang about as we had to get down before sunset. Looking down the valley there was no exposure that was even close to capturing the whole dynamic range:

There was a lot of motion in the people climbing down (especially the dog) so I couldn't do a straight HDR without getting motion halos. I stacked the images in photoshop and took the sky from the darkest exposure, the middle ground from the middle exposure and the foreground (and importantly all the people) from the lightest exposure. I'm not 100% happy with the result, it still looks a little too fake but for a quick snap shot and momento of the day it does the job: