[NTG-context] Customize grid layout

Dear TeXers, Is it possible to define the layout like: \setuplayout [grid=yes% ,lines=6% ,gridstyle={1,1,1,3.5,1,1}% ] so that I can have 6 lines per page, but the 4th line skips will be 3.5\baselineskip. For your information, the blank between the first 3 lines and the rest ones is used to display the page number (it's not a joke although April is close). I was thinking putting an invisible rule after each CJK glyph as a font feature, and the height of the rule changes every 6 lines starting from 4. But \linenumber seems to be an MKII-only counter. Any suggestions? -- Best regards, ℤhichu ℂhen Shanghai Institute of Applied Physics No. 2019, Jialuo Road Jiading, Shanghai, P.R.China Tel: +86-21-39194888