I don't believe that is possible currently, as you can't use the same cert for two different appliances. The SAN is for the DNS Name of whatever so when you access it via DNS modern browsers trust it. You wouldn't use two DNS names for the same appliance. Multiple SANs is only useful when using 1 cert for multiple things. I believe there is a Feature Request being considered for custom CSRs but currently this is the only option.
We are running OpenManage Enterprise version 3.3.1, we have a PKI and I want to use a certificate for the OpenManage Enterprise website. On the Application Settings tab > Security > Certificates, I seem to only be able to define a Distinguished Name and not any Subject Alternative Names (SANs) on the Generate Certificate Signing Request. Would be very handy if I can add SANs to this certificate. If I use DigiCert Certificate Utility to create my own certificate request (with SANs) and upload the certificate, it errors with a 'the certificate you provided is invalid' error - probably as it doesn't have the private key. If I create a pfx with the private key and upload that, I get the same invalid error. Any help greatly appreciated. 
SANs for the OME website certificate request