ssd drive in imac

I have an imac 24'' early 2009.
I want to put in place the existing disk (640 giga) an ssd drive and a sata disk (at 1.8 inches or 2.5 inches tied one over the other) and of course without taking the superdrive.
Seeing the inside of the imac I think they fit in place of the existing hard disk.
My problem is how to give it to the ssd sata interface, (speculation on a sata hub which can connect the output of the sata imac to existing hard disk and will give me two outputs for sata disks). The power supply will get it from the existing hard disk.
Any help accepted
Thanks in advance

Is this what you need? Amazon.com: SILVERSTONE SDP08 3.5 to 2 X 2.5-Inch Bay Converter: Computers & Accessories

Thanks for answer, but I need a speculation on a sata hub which can connect the output of the sata imac to existing hard disk, and will give me two outputs for sata disks.
Any help?

Any help?

Like this? iMac Intel 21.5" EMC 2428 Dual Hard Drive Kit - iFixit

Thanks for answer. But I need a sata multiplier for connect two sata drives in iMac sata output. I found the AD5SAPM sata multiplier from ADDONICS but they aren't sure if this device is compatible.