Logstash: Fetch the end string using grok or other filters

I have a field in my message where I only need the last part of the string but the message length varies for different environments. I tried using grok to fetch the last part of the message but unable to get the expected output

input log

"loggroup" : "test-environment-qa"

or

"loggroup" : "test-dev"

or

"loggroup" : "authentication-group-env-perf"

expected output:

"loggroup" : "qa"

or

"loggroup" : "dev"

or

"loggroup" : "perf"

how to get the expected output in logstash using filters ?

Use mutate+gsub

mutate { gsub => [ "loggroup", ".*\-([^-]+)$", "\1" ] }

The \1 references the capture group (the stuff inside parentheses) which is one or more characters that are not -, anchored to the end of the line.

Thanks @Badger