Inter VLANs traffic needs to be routed and hence pass through a Layer 3 device. That means you can use access-lists on the L3 device to permit and deny traffic to pass from one subnet (=VLAN) to another. The access-lists can be applied to the physical or logical (VLAN interfaces) you use.
Private VLANs create sub-VLANs within a VLAN and are usually better suited to apply traffic limitations between ports in the same VLAN. However, depending on what you actually want to achieve, Private VLANs may be a good, or better, solution if you now have created different VLANs for single hosts (but we would need more information about your requirement).
HTH, Thomas
