Hello SamiraBraund39417~
There is not...
What I do is I periodically paste in chat (your panelists can do this also) is "Please remember to ask your question to ALL PANELISTS or your question may not get answered" At the beginning of the session I also mention in in my "housekeeping" and show a screenshot of the Q&A panel with Ask All Panelists circled.
This has worked for me in the past. The key is every 15 minutes or so pasting the nice little reminder in chat. I also disable chat for attendees so they don't put questions in the chat panel. The host can do that by going to the top left menu bar, select Participant > Privilege's > For Attendees > then uncheck all chat options. Then its only Panelists that can use chat!