No it is not possible to do this and you must concatenate both files together so you can use one file with a list of all the CAs in it.
The easiest way to do what you want is to have the certificates in directory, symlimked to has file name, and then use SSLCACertificatePath instead.
The process to create the has filenames of each link is detailed here:
When you install multiple CA certificates in a single directory, you can
calculate the hash for each file (NAME-OF-CA-FILE) by using the command:
openssl x509 -noout -hash -in NAME-OF-CA-FILE
Once you know the hash (HASH), you can then rename the file so that
OpenSSL can find it:
mv NAME-OF-CA-FILE HASH.0
However, this is a little unfriendly for the system administrator, since
it is not obvious what CA certificates are present. So many people
choose to keep the original name of the file and create a symbolic link
to that file for OpenSSL:
ln -s NAME-OF-CA-FILE HASH.0
This way, OpenSSL can find the correct CA certificate efficiently, and
system administrators can know what CA certificates are present.