No, it's very simple really, just takes a bit of effort on the part of the people doing the rosters. I hand wrote rosters for years and we had a number of Husband (pilots) and Wife C/A's) teams. Identify the trips and days off, pre assign the same to each couple and away you go. There has to be a little understanding especially from other crews, and the couples don't pinch all the good trips or weekends off.