Creating a Custom Transformer with a group of similar attributes ( number of attributes = undetermined ) as input and output

I would like to create a custom transformer where I can submit a group of attributes ( e.g. all datetime ) and have the output back into the same attributes. Similar to the 'DateTimeConverter' or ' StringReplacer' which allows for the selection of multiple attributes to perform a transformation upon.

Is this possible? If so, how as I am unable to find documentation . Other suggestions greatly appreciated.

Many Thanks