Alarm Pipeline - Array of rosters

I have alarms that need to be sent to multipe rosters. The rosters are configured for each alarm by the users. To accomplish this i have configured it as follows:

The alarm has a configured custom property “rosters” that is of type “string array”. Each element of this string array equals the name of a configured roster.

How can i setup the alarm pipeline so that the notification can be sent to several rosters using a string array custom property?

Got help from Marcus on support. A little tweaking and this works great.
See attached export.
global_2018-12-03_1716_partial.proj (7.0 KB)