variable in COMPOSE Mapping filter

[jonaguada]

We have a load in compose where we filter for a subset of customers in a separate DW.  The current way that we segment these customers in the separate DW is by using the filter shown below.

Anytime we get a new customer, we have to update the filter in most of the tables.  I would like to centralize the CustomerID values into one place and simply update the customerIDs in that one place.

I was thinking of two ways to do this:

1. Create a variable that would contain these values. The filter could look something like the following....

      ${CustomerID}  in vCustomerList  where vCustomerList is created somewhere in COMPOSE

2. Tablize the CustomerIDs and have a filter that looks something like the following...

      ${CustomerID}  in (Select distinct CustomerID from ListOfCustomersTable)

Are either 1 or 2 possible?