Mixing justifications on the same line

I found myself resorting to something like,

@Tbl margin { 0f }
 aformat { @Cell @ZeroWidth A | @Cell width { expand } | @Cell B | @Cell width { expand } }
{
@Rowa
  A { Left-justified thing }
  B { Centre-justified thing }
}

Could I have done this more simply with @Centre and @OverStrike and
suchlike? Maybe I should have a closer look at how fancy headers and
footers are done. I am wondering what I shall do when I want a
right-justified thing too!

Mark