> Try
> \starttext
> Foo Baz \inmargin {Blerf \\ Baz}
> \stoptext
Hmm, that might work, but my real case is slightly more complicated. I have
the \inmargin wrapped in a \refdef command, that references some topic on some
page. So I say \refdef{foo} and it looks up both the text and page number for
foo and puts that into the margin.

I could probably complicate my \refdef command into taking multiple references
at the same time. However, that will still require me to merge those commands
when they are close together, which might mean some of the rerefences are not
in their logical place anymore. For example:

  Some short paragraph referencing foo. \refdef{foo}

  And another paragraph refering bar. \refdef{bar}

This has the references in the logical places. With your suggestions, I must
change this to:

  Some short paragraph referencing foo. \refdef{foo,bar}

  And another paragraph refering bar.

Which is more error prone when I start moving around text... So, it's a
workable solution, but it's not quite ideal yet...

Gr.

Matthijs