There are 2 ways you can achieve this; 

• Enable FKM plugin > Advanced tab > Parse trigger details, plus, the use of either Tags option below the Key settings on the FKM Key window, or via the FKM plug-in Advanced tab > Tags.
• Tags configured via the FKM key level supersedes the Tags specified in the FKM plugin Advanced tab > Tags.

For example, you have configured an FKM key, either FAIL or WARNING to match a string of words, i.e. "The quick brown fox", but wish to only display the word "quick brown" in the metrics view, then you will have to employ the use of the Tags option, either via the FKM Key level > Tags option, or via the FKM > Advanced tab > Tags. 

A file which contains the following text. Inside the file there are 8 lines of the string "The quick brown fox"

The Fail Key is set to be the string "The quick brown fox"

And the resulting dataview follows.

If we want the columns, status and triggerDetails to display the words "quick brown" as opposed to "The quick brown fox" every time the FAIL key is encountered we can do the following.

Make use of the Tags option via the FKM key level.

This would alter the prior dataview to the following one. 

However, only the status column changed, and not the triggerDetails. We also need to enable the Parse trigger details found via the FKM plugin > Advanced tab

Doing so, would produce the following dataview.

As mentioned, another way of achieving the same result would be via the FKM plugin > Advanced tab