documentclass{article}
usepackage[xindy,nonewpage]{imakeidx}
usepackage{filecontents}

makeindex[name=indexA,title=Index A,options=-M indexA.xdy]
makeindex[name=indexB,title=Index B,options=-M indexB.xdy]

begin{filecontents*}{indexA.xdy}
(markup-index :open  "~n
begin{theindex}
  providecommand*lettergroupDefault[1]{}
  providecommand*lettergroup[1]{%
    textsf{#1}
    nopagebreak
  }
  ~n"
  :close "~n~nend{theindex}~n"
:tree)
end{filecontents*}

begin{filecontents*}{indexB.xdy}
(markup-index :open  "~n
begin{theindex}
  providecommand*lettergroupDefault[1]{}
  providecommand*lettergroup[1]{%
    textit{#1}
    nopagebreak
  }
  ~n"
  :close "~n~nend{theindex}~n"
:tree)
end{filecontents*}

begin{filecontents*}{latexmkrc2}
$makeindex = 'texindy -M indexA.xdy %O -o indexA.ind indexA.idx'; #$

$pdf_mode = 1; #$
end{filecontents*}

begin{document}
Term Aindex[indexA]{Term from index A}
par
Term Bindex[indexB]{Term from index B}
printindex[indexA]
printindex[indexB]
end{document}