1-Can either man talk to you?
2-Did either man talk to you?
The dictionary says that 'either' as an adjective can mean either 'both' or 'one or the other'. But could it mean 'both' in these sentences? Could one use them instead of:
3-Can both men talk to you?
4-Did both men talk to you?
The answer to the first pair of questions could be one man or both men, so I wouldn't see them as replacement for the second group.