http://www.nzherald.co.nz/section/1/story.cfm? c_id=1&objectid=10431062
I think this is the story the cartoon is referring to. 'Hello, hello, hello' is what policemen are traditionally supposed to say when they see something suspicious (they don't really, it was a sort of 1950s joke.) Anyway, according to this story police are alleged to have been involved in some sort of group sex, which is what 'group action' means in this case. The women in the picture are meant to be prostitutes, and what the caption means is that if she was approached by men wanting group sex she would assume they were cops.