Have you heard of the phenomenon that girl friends' periods get synchronized when they are in each other's company (for a certain period of time)? [Details inside].

To make it more clear: Say, Ellen used to have her period at around the fifteenth of the month and Gina around the twentyfifth of the month, but after a while, when they are in close company for a period of time (months?) their start dates will be the same (about).
My girlfriend has experienced this, with multiple girl friends.
Have you heard of this?
Is it a known phenomenon?
If so, what causes it?
Can males (partners or friends of the female) also get similar symptoms (belly ache) when her period is there?