Train wildcard signals for multiple different items

[Kopie115]

Currently item wildcards pick just one item

Instead, we could have a multiple wagon train, with each wagon having a different item, and the wildcard signal would read each one of the wagons separately in order

e.g.:
Train with 3 wagons: Plastic, Sulfur, Explosives (in this order)
would go to a Train stop named "[Plastic][Sulfur][Explosives] Output"

This would have some limits, e.g. working only if (the amount of wagons) == (amount of wildcard symbols used)