"Create New Group" is grayed out in Visualize 2017 whenever I select multiple parts. Anyone know why?

You have to make sure they are on the same twirl order. So you can group 2 parts or group 2 parts but not group a part and a group together. See images below.

Or you might need to merge models first then group within that model

After grouping select pivot tool to position it to the exact spot needed.