Finishing the first round with four wins from five matches, the bankers progressed virtue of their second place in Group B to face Bangkok Bank A, who still have one game in hand, in the semi-finals.
Rattanabundit will take on Hi-Tech, the second-placed finishers of Group A, in the other semi-final clash.
In Group-A action, RBAC got off the bottom of the pile with a 66-35 victory over Raknamjai.
In the men's division, Bangkok Bank crushed Sunspark, the youngest team in the tournament, 96-63 to end their first-round campaign with four wins from five matches in Group A.
Bangkok Bank's hopes of advancing lie in the hands of Hi-Tech, who play Royal Thai Air Force today in their last group game.
If former champions Hi-Tech lose, they will have nine points as well as the bankers and the Air Force, thus causing the organising committee to hold a draw to see who advances.
However, if Hi-Tech win, Bangkok Bank will move into the semi-finals as the second-placed side in Group A.
The semi-finals and final will take place at Hua Mark Indoor Stadium on Monday and Tuesday, respectively.