In Slack, how to find conversations (threads) that involve two specific persons

I can use from:@Some Person and to:@Some Person in Slack search but that doesn't find plain mentions, or just interactions between two people when they don't necessarily tag each other.

My use case is that I've been involved in a discussion (thread in some channel) with another person from the company but can't remember any keywords that would return search results. I'd like to construct a search query like this:

involves:@Borek Bernard involves:@Other Person

But Slack doesn't support the involves keyword (like e.g. GitHub does).

I have tried two "from:" operators but get zero results as well:

(doesn't work either)from:@Borek Bernard from:@Other Person

Is there a way to search Slack for two people?