Is there a way for me to get it to use the second one when the first one cannot be resolved?
The DNS resolver will only move onto the other name servers if the first one returns an error (i.e
SERVFAIL) or can't be reached. If the DNS server returns
NXDOMAIN then the resolver considers that the proper answer and won't check the others.
NXDOMAIN is considered a final definitive answer that the requested domain does not exist.
If you're asking this because you have a local DNS server that's authoritative for a local domain, then you should set up forwarders on that DNS server so that it can resolve all your domain names for you. You can still list the non-local DNS after that one in
resolv.conf as a precaution against failure, but your local DNS has to be first because the other DNS servers returning
NXDOMAIN will stop name resolution.