I have successfully used Transitland to extract a single agency from a GTFS file into a single file (similar to this question). However, my huge national GTFS data set has about 900 agencies, and running this command takes about 10 minutes to extract a single agency because the input source is huge.

I want to split this huge GTFS file into 900 GTFS files, one file per agency, such that I can pop up 900 TheTransitClock instances programmatically to generate live times which only supports a single agency.

How can I do it using Transitland without looping the command for 900 times, as it will take days for 900 invocations?