sort array and array_unique

[bampot]

Array (
[0] => 2 [product_group_id] => 2
[1] => Parts [group_name] => Parts
[2] => [description] =>
[3] => 2 [theme_id] => 2
[4] => 2
[5] => 38 [product_sub_group_id] => 38 )

i would like to check arrays like this with array_unique and remove any duplicates in [group_name],

how could i go about this?

thanks in advance