Filtering match

Is there a way to exclude items for the list generated by the match tag?

<match postag_regexp="yes" postag="WKW.*"/>

currently the suggestion is often ‘beurt|gebeurt’, which could be correct, but in 99% of the cases the suggestion has to be ‘gebeurt’.

<match postag_regexp="yes" postag="WKW.*" regexp="yes">gebeurt</match>
will not do, since there migh be more. I really need to exclude.