How to create a Privatemsg thread with multiple recipients in a Rules component? I'd like to send private messages to a selected group of users. For this purpose I use a view with VBO and a Rules component action (utilizing the "Send message" action provided by Privatemsg) - as  described in this question.

However, I still have a minor issue with it: Since I send the messages looping through the list of users, privatemsg module sends individual messages and doesn't create a thread with multiple users. Is it possible to use the whole array of users in a single "Send message" action? 

Probably one solution might be to use cutoms PHP code in rules component and create thred with privatemsg_new_thread function. But it's not a very drupalish way, I guess.
I found a solution using a rule component with custom php code. It needs some changes in privatmsg module, see in this discussion: https://www.drupal.org/node/2725325