riser card question

[AP2]

i currently have a mini itx mobo for a small file server with 1 pci-e x16. currently the pci-e x16 is occupied by a graphics card, but i would like to add a raid card to the system. could i use a pci express riser card with 2 slots to achieve this? basically turning 1 pci-e x16 slot into 2.

thanks