You can take the airport shuttle bus to Wulinmen, then take a taxi to Hangzhou East Bus Station. There you can find bus from Hangzhou to Jiashan. After arriving Jiashan, you can take bus or taxi to Xitang.
You can also take the airprot shuttle bus tp Hangzhou train station and then take train to Jiashan. Then take bus to Xitang.

Thank you for your prompt reply Ms Frankenstein.
I think i choose the second option from Hangzhou train station to Jiashan.

Love this website when traveling to China.