Use a diretiva NameVirtualHost:
NameVirtualHost *:443
defina seus vhosts:
<VirtualHost *:443>
ServerName www.studyhat.blogspot.com
DocumentRoot "/opt/apache22/htdocs/siteA"
SSLCertificateFile "/path/to/my/cert"
SSLCertificateKeyFile "/path/to/my/key"
</VirtualHost>
<VirtualHost *:443>
ServerName www.studyhat.wordpress.com
DocumentRoot "/opt/apache22/htdocs/siteB"
SSLCertificateFile "/path/to/my/cert"
SSLCertificateKeyFile "/path/to/my/key"
</VirtualHost>