Guys, I'm affriad it is not as simple as that.
Firstly, T4S (the sattelite part of T4) is split into two parts. With one half of it is designed for long haul non-schengen destinations, the other half is designed for short haul destinations inside schengen.
Therefore, whether it is T4 or T4S communicates nothing.
[T4 itself is generally geared for shorthaul destinations in schengen.]
However, this is just what it is primarily geared up to, there are huge exceptions too!
Example in question:
Iberia flights to Heathrow go from T4. [Even though the UK is not part of (this) Schengen area.] - And BA code share on these flights.
But BAs own flights to London go from the non-schengen part of T4S! - Which Iberia code shares on.
Generally, the only Iberia operated flights from the non-schengen part of T4S are long haul. All other Iberia flights go from T4 or (the schengen part of) T4S.
All other oneWorld airlines generally go from the non-schengen part of T4S [Even to destinations inside schengen.].
THERE ARE EXCEPTIONS.
Remember schengen is only about imigrational controls, not customs. [And Spain's north african enclaves, plus the canary islands are not part of the normal EU VAT area, but are part of Schengen.] Schengen entry/exit checks can be easily done regardless of which terminal you fly to from.
Further, remember that it is possible to route people different ways from the same air bridges depending on the status of the flight!