Here is another basic example of pairing of fonts from the same family.

In the first example the Burdigala V, a simple but distinct sans, is both the main title font and subtitle font. Not exactly groundbreaking, but it works nicely because the two are set in different sizes and weights. They work together as it were.

The second one speaks for itself. It demands a more powerful font, in this case the slab serifs of Burdigala M, to support a phrase like this. A descrete sans font like Burdigala V is all you need for the subtitle.

The third example requires a fancy kind of font, here the classy Burdigala C, to convey a message like this. And just like the second example above; a neutral sans font (Burdigala V) in the subtitle.

/ap