With 11 and 1/2 hours of play you only have time enough for 6 rounds of play. The numbers are clearly going to work out best if you have 9 or 12 teams, since 6 teams playing in each of 6 rounds means 36 slots available, a number which is exactly divisible by 9 and 12.
With 12 teams you can randomly assign the teams to two groups A to F, and G to L and then have alternating rounds where all the matches are played within a group. If you do this, clearly no team plays in two consecutive rounds and all teams play exactly 3 matches.
AB CD EF
GH IJ KL
AC BE DF
GI HK JL
AD BF CE
GJ HL IK
With 9 teams I took rounds 1,3,5 & 7 from the 9 team round robin (see the "Court balanced Round robin" topic for the Excel file I used) and rearranged the rounds by hand to give.
BI CH DG
DB EA FI
FD GC HB
HF IE AD
BC IA EG
EF GH AC
Here there will always be at least 3 teams who play again in the next round, since two rounds has 12 slots and there are only 9 teams available to fill them. So the schedule above is close to being optimal since only in the last round do 4 teams play again. Team D is the only team that plays four times in succession.
Ian.
