Fred,
I am not sure that I understand the format of play, so it would be helpful if you could explain why you want some of the palyers to be fixed like this? Have you seen the whist schedule for 12 players that can be found by clicking on the schedules link near the top of this page? This is an 11 round solution which has with-each-person-once and against-each-person-twice properties, but only one player can remain fixed to a table - the rest have to move.
If I follow your suggestion and 1 & 2 partner in round 1, and then remain fixed to a table for the rest of the tournament, then surely they have to play against each other as opponents for all of the remaining 10 rounds? Also there will not be enough partners for them, 10 rounds and only 8 partners (5 to 12) to choose from.
Ian.