Watching everyone?

[Busy ECE mommy]

It could be attention-seeking behaviour, or just testing boundaries to see your reaction.
If I’m sitting doing an activity with a few children, and others are engaged in another activity, I make eye contact and do verbal “check ins” from across the room. I might comment on the skills they are using well, or describe or ask them about their play. The kids then know that I’m paying attention to everybody even if I’m not right beside them.
I like Suzie Homemakers suggestion. Could you section off a part of the room with a large divider gate so all the kids are in the same area as you? The gate could be moved as you move to different areas of the room.