I'm behind the times to the date.
Is it currently a construction mod (like Planetary Launchpads, USI, WBI or so) where you can specify not just "1200 Rocket Parts", but "100 Metals, 20 Chemicals, 40 Plastics" to fabricate a "1 Mainsail Engine" in situ?
Is there a TechTree mod where you can specify that "Mainsail" node gets available only after "Terrier" was built?