one or more terms around a tagged term can be found. Therefore you need to identify first all terms that can be tagged, e.g. using a tagger node. Convert the tagged documents to a bow, then the terms to strings and then group by the strings. You end up with a column of unique strings.
Use these strings as a dictionary with the wildcard tagger. Before doing this, add some regular expressions to the strings in order to search around these strings, e.g. "([a-zA-Z]+ )*" + <myString> + "( [a-zA-Z]+)*". Therefore you can use e.g. a Java Snippet node. Then use the reg exed strings as dictionary. In the Wildcard tagger select "sentence based" and "regular expression".
Attached you find an example workflow. Hope this helps.