It's not possible to group them together like this, because the accept event is not attached to the same post.
When you offer a bounty on a question, the bounty event is attached directly to the question, which is why bounties get grouped together with the rest of the events for the question. Same ID.
When you accept an answer to your question, the event is attached to the answer you accepted, not the question. You gained 2 reputation for an action on the answer, similar to how you'd lose 1 reputation for downvoting an answer. Those events shouldn't be grouped into the question's events because they are not events on the questions themselves. They're completely separate posts, and should be linked to the post where the event actually occurred.