[NTG-context] Defining hyphenation sites that will not produce a dash?

Hello My ConTeXted XML document contains a number of constructs like this pRS&thinspace;403&endash;<math><mn>9</mn><mo>×</mo></math>Myc/TEV/<i>URA3</i>/TEV/His₈ (molecular genetical plasmid/genotype deinitions - in case you wonder ;0). This predictably produces line break/hyphenation trouble. I'm already using a mapping rule like this \defineXMLargument [hyph] {\-} but I was wondering whether there's an analogue that won't produce a hypneation-dash if the manually defined hyphenation site is used. Thanks for any hint, Joh