The different rules for different ethnical groups already apply to handshakes. As Malaysia is a Muslim country, physical touch between sexes might be seen us inappropriate. Malay women do not necessarily shake hand with men. To be on the safe side, wait for the woman to reach out her hand first. Only then is it appropriate to shake it. If the woman does not extend her hand, only bow slightly with your hand placed over the position of your heart to demonstrate respect.
When you shake hands with Chinese business partners, it is appropriate to shake hands with a woman, but wait for her to reach out her hand first. As for men, shake the hands only lightly but prolonged.
When being introduced to Indian business partners a nod and a smile might be sufficient, but shaking hands is allowed.