WATCH: Ulster director of rugby Les Kiss explains selection around festive period
It raises its head every year, the selection by all the Provinces for their teams in their respective Irish Guinness PRO14 derbies.
Injuries, National player welfare and rotation within the Ulster squad are all reasons for the changed sides during the derby encounters.
But sometimes other issues can arise which has to be dealt.
Les Kiss gives a little insight into the selection situation - an issue which has left fans venting their frustrations on social media.