You can only assign one license key to a host, but a key for just 1 CPU is not sufficient for a host that has 2 CPUs.
So you need to combine the 12x 1-CPU-keys into 6x 2-CPU-keys or fewer instances of more-CPU-keys. You can even combine all 12 keys into a single 12-CPU-key and use that for all your hosts (although you really only need 4 CPUs for your 2 hosts).
The required manipulations of license keys can be done on the my.vmware.com portal using the VMware account that these licenses were registered to. If in doubt ask your reseller on how to handle this.
- Andreas