[NTG-context] font encodings

Hi all, I want to use a custom font encoding (in my case, enco-agr for ancient Greek). I can't set it up for the entire document because it breaks, e.g., the output of accented letters. But when I try to use it for certain parts of the document only, it will insert a line break whenever it is used. So my question: is it possible to switch font encoding in mid-paragraph? Best Thomas