GOOD TO KNOW IN USA

Arguably one doesn't need anything more powerful than 5mw for scope mounted use because one is looking at the beam close to ON Axis. However for the OP's purposes unless we are talking 2 or 3 people standing right beside him, then a higher power laser would be more appropriate. 15-20mw would be more than enough for the beam to be seen by those at the edge of the group perhaps 20ft away. (Assuming the laser is kept warm. They are much fainter when cold or don't work at all) I got my 10mw from Wickedlasers