<reference name="root">
    <action method="unsetChild"><name>breadcrumbs</name></action>
    <block type="page/html_breadcrumbs" name="breadcrumbs" as="breadcrumbs">
        <action method="addCrumb">
            <crumbName>First</crumbName>
                <crumbInfo>
                    <label>First custom</label>
                    <title>First custom page</title>
                    <link>/</link>
                </crumbInfo>
        </action>
        <action method="addCrumb">
            <crumbName>First</crumbName>
                <crumbInfo>
                    <label>Second custom</label>
                    <title>Second custom page</title>
                    <link>/second</link>
                </crumbInfo>
        </action>
    </block>
</reference>

First custom page > Second custom page

First custom page > Second custom page > Home > Title of CMS page