When we were looking for couples I geuss it would have to be compatability between the four.
Not so much friendship.
As far as single males,
Some have been friends beforehand, some have not.
But as I have stated in another thread that I started, letting singles too close to our personal life has not to work out too well.
They seem to get possessive over Mrs naughty
Friendship from a distance or meeting someone at a club seems to work the best.