You could, of course, run two separate sections and combine the results afterwards, but unless you have exactly the right number of tables you are still likely to have spare board-sets in circulation - and then there's the problem of uneven section strengths, the possibility of a three-board sit-out if there's a half-table, and it's simply a better competition if you play against more pairs.
It can also be adapted for 10½ tables as well as 11½ tables, although the 11½ needs players who know what they are doing!
Imagine your tables arranged in a circle with tables 1 to 10 round the circumference and table 11 at the centre. Give out 9 sets of boards onto tables 1 to 9 respectively. Table 10 always shares with table 1. Table 11 shares in turn with table 9, 7, 5, 3, 1/10, 8, 6, 4 and 2.
As you can see the fifth round is a 3-way share at tables 1, 10 and 11 but it usually works okay – especially if the club takes a tea interval after the fifth round. Boards move down one table round the circuit 9 to 1.
Just to add fun to the movement you arrow-switch the last round at all tables. The Manning movement manual also says to switch at table 1 on round eight as well.
You set up the room as for the 11-table movement. On the first round NS 12 sits out. On the second round they displace NS10 (but keep their pair number 12). NS10 sit out on round 2 and on round 3 displace NS9. The movement continues like this with a NS pair sitting out and then displacing the next lower pair. The important thing is that the NS pairs keep their original pair number.
The 10½-/ 11-table movement cards are on pages 82/83 of the EBU Movement Manual (edited by the late John Manning) available from the EBU Bridge Shop (01296 397851).