loop results to display only unique column values

[Cherichoc-]

How can I display 

in json (in txmlMap with Accountnr and devid set as loop elements)

{entid:62 , accountnr:[EEE, AAA], entityname:boss, devid:99 ,device:boz}

instead of

{entid:62 , accountnr:[EEE, AAA], entityname:boss, devid:[99,99] ,device:boz}