Get Latest Reply to Each Conversation Returned by Messages LiQL Query

I have recreated our message list with various filters. I am using a JSON messages query with a replies subquery. I am getting messages for the board with depth=0 (topics) sorted by conversation.last_post_time.

For example:

<#assign solvedMessageCall = restBuilder()
            .method("POST")
            .path("/search")
            .body(
                [
                    {
                        "messages": {
                            "fields": [
                                "author.avatar.message",
                                "author.login",
                                "author.view_href",
                                "author.rank.name",
                                "author.rank.icon_right",
                                "author.rank.color",
                                "author.rank.bold",
                                "subject",
                                "post_time",
                                "post_time_friendly",
                                "view_href",
                                "replies.count(*)",
                                "metrics.views",
                                "user_context.read",
                                "replies"
                            ],
                            "constraints": [
                                {
                                    "board.id": "${boardId}",
                                    "depth":0,
                                    "conversation.solved": true
                                }
                            ],
                            "sorts": [
                                "conversation.last_post_time desc"
                            ],
                            "limit":results_list_size,
                            "offset":offSet,
                            "subQueries": {
                                "replies": {
                                    "fields": [
                                        "author.login",
                                        "author.view_href",
                                        "author.rank.name",
                                        "author.rank.icon_right",
                                        "author.rank.color",
                                        "author.rank.bold",
                                        "post_time"
                                    ],
                                    "limit": 1
                                }
                            }
                        }
                    }
                ]
            ) />

Because I can sort by conversation.last_post_time the order is correct and matches the out of the box message list. So far so good.

However, I also want to show the latest reply to the conversation like this:

The replies subquery is giving me the latest reply to the topic post, not necessarily the latest reply to the conversation which might be a reply to a reply. The out of the box message list shows the correct latest reply. Is there any way to recreate this without having to make additional API calls?

Thanks!