
\def\startMyCite#1{\startbuffer[#1]\startlines[#1]}
\def\stopMyCite#1{\stoplines[#1]\stopbuffer}

\def\getMyCite#1{%
  \startlinenumbering[{\in[lr:b:#1]}] % the result of \in[lr:b:#1]
    \getbuffer[#1]
  \stoplinenumbering}

\starttext
\startlinenumbering
  \someline[lin:a] We thrive in information--thick worlds because of
  our marvelous and everyday ca- pacity to select, edit, single out,
  structure, highlight, group, pair, merge, harmo- nize, synthesize,
  focus,
  % \startline[test]
  \startMyCite{test}
    organize, condense, reduce, boil down, choose, categorize,
    catalog, classify, list, abstract, scan, look into, idealize,
    isolate, discriminate, dis- tinguish, screen, pigeonhole, pick
    over, sort, integrate, blend, inspect, filter, lump, skip, smooth,
    chunk, average, approximate, cluster, aggregate, outline,
    summarize, itemize, review, dip into, flip through, browse, glance
    into, leaf through,
  \stopMyCite{test}
  % \stopline[test]
  skim, re- fine, enumerate, glean, synopsize, winnow the wheat from
  the chaff and separate the sheep from the goats.
\stoplinenumbering

\inline[lin:a] % 1--1 instead of 1
% \inline[test]

\getMyCite{test} should output

\startlinenumbering[3]
  organize, condense, reduce, boil down, choose, categorize, catalog,
  classify, list, abstract, scan, look into, idealize, isolate,
  discriminate, dis- tinguish, screen, pigeonhole, pick over, sort,
  integrate, blend, inspect, filter, lump, skip, smooth, chunk,
  average, approximate, cluster, aggregate, outline, summarize,
  itemize, review, dip into, flip through, browse, glance into, leaf
  through,
\stoplinenumbering

\stoptext

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