markmagic,
K-Lo is correct about needing a little more information. Some cardrooms enforce a must move rule instead of trying to balance two tables with the same limit game. If I understand your situation, there are two games and one is breaking down. If you have to fill the main game the first option should go to players already seated. The only way any of this makes sense is if there are not enough players, including the list, to make two full games. Example; Main game table goes to 7 players, must move table down to 6 players and 3 new players walk in the door and want to play. The players from the must move secondary table must be given first option for the three empty seats in the main game. The remaining 6 players will either play short handed, (if they agree) or they will wait for a seat to open in the main game. The list should be according to seniority. This is a common practice for anyone that works graveyard when games begin to break and you are trying to keep a solid game going until the day shift arrives. I personally prefered trying to balance the two games as best I could, an example would be eight player's at each table after the new player's arrived, but some rooms are very strict with the "must move" ruling, by that I mean the main game must always be 10 handed.
I hope I'm at least close to your situation.