Marking the same holes In Creo parametric 2.0

What you're asking for is not, to the best of my knowledge, possible. Unless you specifically sketch such a thing.

Also, this is not something that is standard for any drawing I've seen. When I have to identify holes that are the same I will mark each individual hole with a letter, like "A", or "B" and reference that letter in the dimension. Something like

1/4-20 THRU

(8 PLACES, "A")

Is it tedious? Yes. And don't forget to associate all the letter designations to their respective views.