Feature Description:
Let the Station Control Combinator (SCC) accept network and priority signals in addition to the item signal, combining them.
Example:
Provider station where the Cybersyn Combinator (CC) receives the current stock (of say, stone and sand), request threshold and priority.
Additionally the SCC receives an item signal (to purge say, stone), a higher priority than the CC and a different (sub)network.
When stone reaches the purging threshold, a single train is fetched according to the additional signals the SCC receives, as in it would deliver to a matching station on the different (sub)network and be served as a higher priority. Additional item signals to the SCC would use the same priority and network, effectively letting you use two priorities and network masks per station; one set for normal operation and one set for purge orders.
Currently:
Now, it seems to have the network signal fed to the SCC to always be in effect. The priority signal seems to completely override the one fed into the CC for the purged items, potentially purging an entire station instead of just surplus. Liquids where you need the constant flow, like from oil cracking, you'd imagine to send a purge signal if one of the three is close to being full. This only results in the entire stockpile being drained into "waste management".
My current issue, for perspective:
Playing Nullius, I'm setting up a block to crush sandstone which results in sand and stone. The stone is essentially worthless to me, so I want it sent into my waste management system (for voiding) which I've dedicated the A2 subnetwork to. I want the sand available in the provider, but there's other stations which has sand as a byproduct (so it needs to be actively purged from those). So, if I set the SCC network to A2, the sand from the sandstone crushers are promptly sent to voiding.
Further down that line I produce wastewater, which has a few uses so I need it provided to the primary network. But I can't let it go full or my entire voiding operation stops, so I have to scrape off the excess, but.. as soon as it hits the purging threshold I get a stampede of trains that drains the entire station to void it all.
