Multiple Promotions - Best way to show on Resume

Hello,

I've been with my company for almost four years now and have received two promotions. My second promotion was a few months ago and it was a result of my efforts and taking on extra responsibilities. So the position itself didn't actually come with any new responsibilities, just a title and a pay raise with the expectation that I keep taking on new responsibilities and performing at a high level.

I'm starting to look elsewhere so of course I want to update my resume. However, because my new position doesn't have any new responsibilities, I'm not sure how to structure my resume. Because my current position doesn't have more than two accomplishments that are specific to it, I see three options (I've been leaning towards number 1).

1. Separating all three positions but listing all of the roles/accomplishments from my previous position that are ongoing under the new position's title (leaving just a few under the previous position).
2. Grouping my current position's and my previous position's roles together under a title that lists both positions and dates.
3. Separating all three and only listing the two accomplishments specific to this position under its title.

Thanks in advance for any advice,

Josh