ezpublish.yml

## Configure db connections ##
doctrine:
    dbal:
        connections:
            repo_one_connection:
                driver: pdo_mysql
                host: localhost
                user: repo_one
                password: foo
                dbname: repo_one
                charset: UTF8
            repo_two_connection:
                driver: pdo_mysql
                host: localhost
                user: repo_two
                password: bar
                dbname: repo_two
                charset: UTF8

## Match repos to connections
ezpublish:
    repositories:
        repo_one:
            engine: legacy
            connection: repo_one_connection
        repo_two:
            engine: legacy
            connection: repo_two_connection


## Configure groups with repos and cache_pools ##
    system:
        repo_one_sites_group:
            cache_pool_name: "repo_one_cache_pool"
            repository: repo_one
        repo_two_sites_group:
            cache_pool_name: "repo_two_cache_pool"
            repository: repo_one

## Configure cache pools: default for fallback
## repo_one_cache_pool & repo_two_cache_pool for repos

stash:
    caches:
        default:
            drivers:
                - FileSystem
            inMemory: true
            registerDoctrineAdapter: false
        repo_one_cache_pool:
            drivers:
                - FileSystem
            FileSystem:
                path: '%kernel.cache_dir%/stash_repo_one'
            inMemory: true
            registerDoctrineAdapter: false
        repo_two_cache_pool:
            drivers:
                - FileSystem
            FileSystem:
                path: '%kernel.cache_dir%/stash_repo_one'
            inMemory: true
            registerDoctrineAdapter: false

Great work. I'm trying to unify two installations in a single multi-repository installation. Having one stash cache pool per site access is a better way to have multirepositry installations?