I don't know what the project, goals, audience, etc., are, but one
possibility is to encode the <lb> elements as they lie, and instead
split the <roleDesc>, which also avoids the tag abuse of <trailer>.
<role>Antipholis [Sereptus] of Ephesus</role>,
<roleDesc id="rd1a" next="rd1b">Twin Brothers, and Sons
<role>Antipholis [Erotes] of Syracuse</role>,
<roleDesc id="rd1b" prev="rd1a">AEgeon and AEmilia, but
<lb id="L006"/>unknown to each other.</roleDesc>