The main difference in Halacha between Libo gas Bo and no loibo Gas Bo is the Heter of Baloh Bir.
Normally if a womans husband is in the same city as her and can arrive home at any time there is no issur yichud with her, however if a man is “libo Gas Bo” with her then the issur Yichud would apply.
In addition according to many Poskin including the Beis Shmuel and Chelkas Mechokek if in a case of Libo Gas Bo there is no heter of “pesah Pasuach L’reshus Harabim” a door open towards a public area.
Please be aware that what I have written above is only a very brief synopsis of some very pertinent halachos for any women working in an office or any one with a cleaning lady and other common cases. In any particular situation one must consult a Rav who is versed in Hilchos Yichud.
As for group setting that is a very complex topic and the halachos for ashkenazim and sephardim would differ somewhat and is truly beyond the scope of this forum.