Replace one type of vehicle with a different one.

[Antarctica]

I would like to, across all my 1k feeder bus lines, replace the same, outdated vehicle type with a newer vehicle type (1:1, so if a line had 5 busses before, I would like to have 5 busses on it afterwards).
Is there a function hidden somewhere to do that? If not, would that be something that could be implemented in a future version?

[Vladki]

This feature is available in simutrans-extended