Hello Geoff

If you are confident that true distinction between people and businesses won't occur then keeping them together presents no problem.

However, you still may want your fact table to represent both people and business so you would still require two foreign key values in your fact table to the base dimension so create two views based off this dimension.

By using views, you could then incorporate Business Name verses Last Name as well. Your end users will thank you for it. It's one less thing for them to deal with.

Greg