What I think Mona is referring too is the tearing action that some foreign objects can have when kneaded into a dough. Basically those solid bits tear the gluten strands that you are trying so hard to develop through kneading. This is actually the cause of a lot of frustration when a baker who is used to plain white breads tries to make a 100% whole wheat or multigrain bread. It’s just something to be aware of.
As for trying to keep more of your cranberries in the center of the bread, I would suggest dividing the amount of cranberries you use into two parts. Add the first when you knead the dough, then fold the second part in when you’re shaping the final bread.
You could even leave all of the cranberries out until that shaping stage, roll out the dough, put down a layer of cranberries, then roll the dough up to get a pinwheel effect. I’ve done raisin bread and cinnamon rolls like this, so I know it will work. Just make sure you give the dough plenty of time to proof before going into the oven.
I hope this helps.