Yes. Just keep quiet. Listen to what is being said. Assess when is the right point of time when you can make others aware that you are a part of the meeting. At the most opportune moment, interject and introduce yourself and participate in the discussion. Simple SFB Etiquette. Follow it.
Do you know what happens usually? People join at different points of time in an online Skype for Business meeting. The person joining has no clue about what is being discussed before the point of joining. Unfortunately, most people in the world think that the entire audience is waiting for them to announce their grand presence. Which is rarely the case!
Join as usual. Listen for some time. Get the hang of what is being discussed. Most people who are already in the SFB meeting will notice that you are added to the participant list. Even if they don’t, just give yourself some time to understand the context. If you are lucky, some stupid people who have already joined will talk some secret or gossip thinking that you are not around… enjoy the moment. Finally, when the time is right, you talk and introduce yourself. That’s it. Try it and let me know if it works. If you are the host of SFB meetings frequently, it may be a good idea to educate your participants about it…. by adding one extra line in the invitation itself:
“When you join, your microphone is automatically muted. Even if it is not, mute it. Listen to what is being said and then introduce your presence at the right point of time.”