[NTG-context] Par break/justification problem

I have a paragraph that is formed by two parts: these are normally run together, except when the last line of the first part ends at less than a certain amount max_amount from the right margin. In this case, there should a 'seamless line break', i.e. a line break with the text still fully justified to the right margin. Example: First part of the paragraph: second part is run in and then the text continues. Second example: This is still the first part of the pagrah: second part will now be put on the next line but the last line of the first part should be fully justified. What kind of hskip/penalty/whatever combo should I put between the first and last part for this to happen? -- Giuseppe "Oblomov" Bilotta