sqc assignment

IS it 100 SQK total, or 100 per Favorite List? If I assign a system in Fav.List 0 as SQK1, can an unrelated system in Fav. List2 also be given a separate SQK1 for that Fav. List without also opening SQK1 in Fav.List 0? Or, must I designate a totally different SQK number to the system in Fav...