Timespan on single table column

[eluser]Unknown[/eluser]
Hi all,
New to code igniter but liking it so far. Quick problem, hopefully.

I'm pulling data from a database, returning a time in utc format. This it then being put into a table using the table library. So far so good.

What I want to do is use timespan to format the date difference correctly, eg.
$this->table->function = 'timespan';

However, I only want this to happen on one column - is this possible?
Thanks.