You use the streamexport.metricFamilyWhiteList.cfg to filter the exports to a specific list of counters you want.
The format is
whitelist.1 = <metric name>
whitelist.2 = <metric name>
Release : 3.x
Component : IM Reporting / Admin / Configuration
If you add a metric as say
whitelist.1 = normalizedmemoryinfo
Then edit it to
whitelist.1 = normalizedportinfo
both metrics will remain in the cache and get collected.
If you wish to remove a metric or replace a metric you must remove or comment out that entire line and use a new numerical value for the new metric
E.G.
#whitelist.1 = normalizedmemoryinfo
whitelist.2 = normalizedportinfo
Then recycle the collection using rest.
Configure an Inclusive List of Metric Families