Train Stations: Allow conditional link to storage building

Suggesting the possibility to link a train station to a storage building in the stations context menu to allow conditions like:
"call train/depart train"
IF:
"Storage XYZ" is below/above X units", either a typed number or percentage.
This would ease the load on train networks and the required space to build.
Example:
A train station close to a settlement calls in trains with various food items if the linked food storages drop below 50%. E.g. it only calls in potatoes if the potatoe storage is low. With a setup like this, we do not need to build a station for each food item anymore and can use 1 station for all and additionally save space by cutting down the need of loading modules for buffer storage.

I was going to post a version of this idea but yours is even better. Station size is currently one of the biggest constraints of trains, and by "station size" I mean not just the number of modules but also any protruding track trains need to pull forward.
To elaborate for devs: We often need to make station sizes larger than necessary in terms of load/unload speed when we want to use Arrival Conditions (all modules full/empty) because if a station cannot fully load/unload upon arrival, the Arrival Conditions cease to serve the important purpose of ensuring that the train doesn't get held up at the station.
This is important for lines w/ multiple sources/destinations where a train could get held up at one station waiting for loading/unloading while it could have headed to another where it would have loaded/unloaded instantly. Adding more trains solves this problem but is inefficient if throughput otherwise doesn't require it, and on lines w/ many options it could need many trains.

I'm also frustrated by lack of such functionality, we have this neat loading/unloading logic for trains via single platform, yet no way to utilize it to full potential, inability to effectively use single large train to serve multiple consumers is the main example.
All the needed elements are already in place - existing alert system could be used to track storage fullness - another checkbox in alert setup menu will add building to the list of train conditions (also removing it from alert window to avoid clutter), then in train station UI we will either select the storage from the list (might be to unwieldy for larger factories), or link it similarly to how import/export routes function.