I thinkl best way to do this is use PWM splitter like this.
http://www.swiftech.com/8-waypwmsplitter.aspx
I think there is four way splitter.
Then you use mobo fan connector to make PWM singnal and psu connector to power up fans.
Here is other.
http://www.frozencpu.com/products/20988/ele-1196/Swiftech_8-Way_PWM_Cable_Splitter_-_SATA_Power_8W-PWM-SPL-ST.html