What about creating an official duel room where people could join if they want, it could be as tourney, for example:

AikidoBigDojo Official Duels 1000 TC
AikidoBigDojo Official Duels 500 TC
Wushu Official Duels 1000 TC
Wushu Official Duels 500 TC

or simple

abd : 1000 TC
wushu: 1000 TC
judo: 1000 TC

and ultimate duel room:

abd: 5000
wushu: 5000
judo: 5000

and to ultimate official duel room can join only 3rd dan and higher

I think it's a great idea !