Hello,
which Cisco switch do you have ? The 2900XL/3500XL switches support Private VLAN Edge (Protected Ports).
The PVLAN edge (protected port) is a feature that has only local significance to the switch, and there is no isolation provided between two protected ports located on different switches. In your case, that should be ok, since you have only 1 switch.
A protected port does not forward any traffic (unicast, multicast, or broadcast) to any other port that is also a protected port in the same switch and hence providing isolation. Traffic cannot be forwarded between protected ports at L2, all traffic passing between protected ports must be forwarded through a Layer 3 (L3) device.
Here is a link on how to configure Private VLANs:
Configuring Private VLANs
http://www.cisco.com/en/US/partner/products/hw/switches/ps708/products_configuration_guide_chapter09186a008007e717.html
HTH,
Georg