Group-Level Proxy Chaining

Surge now supports the group-level underlying-proxy parameter, allowing you to configure a proxy chain for an entire policy group in one place. Every member of the group will connect through the specified policy, including members imported via policy-path, include-all-proxies, and include-other-group.

Chained members are represented as derived policies such as Name (via Relay), each with its own independent latency test result. This means automatic policy groups can select the best node based on its actual performance through the complete proxy chain, rather than the performance of the node alone.

The new option is also fully integrated into the policy group editor UI.

Previously, similar behavior could be achieved with external-policy-modifier="underlying-proxy=...", but that approach only applied to members loaded through policy-path. The new group-level parameter works with members from all sources, provides explicit misconfiguration reporting, and is available as a first-class option in the UI. The existing external-policy-modifier syntax remains supported for backward compatibility.

Please refer to the manual for a detailed comparison and configuration examples:
https://manual.nssurge.com/policy-groups/parameters.html