If statements: matching multiple variables in the same column

My question is in attempting to create a new variable based on existing variables.

I have a data set on bunch of different types of classes and class numbers, and whether or not the class was online or offline.

What I am having trouble with is figuring out how to write code to check if there is multiple of the same class that are also different types (i.e. offline or online).

So presumable it would check like this

1. Test Class ,  1, Online
2. Test Class ,  2, Offline
3. Basic Class,  1, Online
4. Test Class ,  3, Offline
5. Basic Class,  2, Offline
6. Test Class ,  1, Offline

so it would report back when two classes match on Class name, class number, and if there is both an online and offline section. Like this

True, False, False, False, False, True

That way I can sort based on the new variable created and compare only similar classes of different section types.