I decided to get the ezUpselling and the Multiple Upselling Links modules and they are great. So to answer my own question about how Multiple Upselling Links works for anyone else who is curious . . .
It is an admin module -- not a customer module. The benefit of this module is that it saves you lots of time by allowing you to add upselling products in groups to a product instead of individually. So if you have a number of products that you want to add multiple upselling products to, this is the module to save you time in that. After installing ezUpselling and Multiple Upselling Links, I was able to finish that part of the project in less than 15 minutes.
