You don't need to share your local storage with other hosts to migrate VMs. XenServer 6.2 supports VM migration without shared storage.
From XenCenter, just right click the VM, select "Migrate to Server" and use the Wizard.
From the CLI, you can use "xe vm-migrate" command.
If you really want to share local storages, the answer depends on how your other hosts look like.
If you want their local storage to participate in this shared storage configuration, you can try something unsupported (these will likely require that you recompile your XenServer's dom0 kernel):
- Some clustered filesystem (e.g. OCFS2, GlusterFS)
The other option is to export each host's local storage back to the pool using NFS or iSCSI. In this way, you will end with multiple Pool-wide Storage Repositories (one corresponding to each host that is sharing their local disks).