Combine several messages from MQTT into one request to DataBase

[SuperBoss9]

The ideal situation is to subscribe to all topics and push all of them into one query.

Now I have something like this that processes each topic separately and put it into DB one by one:

And if I subscribe all the topics then I receive them also as separate objects:

I saw also an example with Batch, that can wait for a number of messages and only then pass them to Join. But this is not a good option due to potential lack of some topics.