<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" 
    xmlns:this="www.example.org/substitutiongroup/ref"
    xmlns:A="www.example.org/substitutiongroup/main"
    targetNamespace="www.example.org/substitutiongroup/ref">

<xsd:import namespace="www.example.org/substitutiongroup/main"/>

<xsd:element name="replace" type="xsd:string" substitutionGroup="A:subsgroup"/>

</xsd:schema>

