It turns out if you left click on the word "Reminders" in Ical, the various lists reminders are in comes up. Decide which list you want to have your reminders merged into. For example let's say you would like to merge "Home" and "Inbox" into "Work." First right click on "Home" and export it, just like you would do with a calendar - maybe give it a different name like "Homereminder." Similarly, export "Inbox." Then, VERY IMPORTANT! Right click on "Home" and "Inbox" and delete each of them. Only after they are deleted, then import "Homereminder" and "Inboxreminder" picking your destination as "Work."
Voila! All of your reminders are now restored in one list.