I have an apache instance running three domains using name based virtual hosting and every domain has resources to reverse proxy them down to an application server. Application
Use the below sequence and test.
ProxyPass /alpha ! ProxyPass /gamma balancer://mycluster4/gamma ProxyPassReverse /gamma balancer://mycluster4/gamma ProxyPass / balancer://mycluster4/ ProxyPassReverse / balancer://mycluster4/