Epic Games Boston Sprinter Signal Problem

I'm hoping someone here can help me.

I am creating a Scenario on the Boston Sprinter in TSW6, and having a problem with a Boston-bound Amtrak Regional passing a Boston-bound MBTA train while on the siding at Attleboro station.

In real life, MBTA train 828 departs Providence station at 9:08AM, and arrives at South Station at 10:26AM. Meanwhile, Amtrak Regional 66 departs Providence at 9:17AM and arrives at South Station at 10:05AM. The only place that Amtrak 66 can pass MBTA 828 is at/near Attleboro station.

When trying to recreate this in TSW6, while the MBTA train is on the siding prior to Attleboro station, the main line track displays an "Approach Restricted" aspect (Yellow over Red). While the MBTA train is boarding passengers at Attleboro, the Amtrak train passes the MBTA train on the main line. Upon leaving Attleboro station, the MBTA train passes an "Approach Limited" aspect (Yellow over Flashing Green).

At the NEXT signal, the Amtrak is stopped, and the MBTA has a "Limited Clear" aspect (Red over Green) and has access back onto the main line.

My desire is to have the Amtrak pass the MBTA at Attleboro and not be seen again until South Station. How can I achieve this?

Thanks in advance.