There is a small icon with a quotation make on it next to the "Quote" icon at the bottom of each person's post. Before you post a reply, click on that small icon on each person's thread that you want to quote from. When you are through with your selections, click reply to thread the quotes that you selected should show up in your text box.
I am not sure if they come up in the order you selected them or the order that they are listed in the threaded.
You can delete the parts your don't want and go from there.
I hope this helps....