Sending Broadcast to users on different groups

I use AD groups for my users pushed on their roster. Some user need to send broadcast to other users located on different groups, so they click 3 user ong group A and then click on another user on group B, but the selection disappear. Using other jabber client it’‘s possible to select users from different groups. It’'s possible to add this feature on spark? Thanks.

Spark 2.5.4 fix it