If we want to read/generate a file that contains multiple record types, and if it is a fixed length file then you would need to use Adv Positional Schema. Where the first value or a value anywhere in the record identifies the type of record.
Example of how this type of data looks like:
PDRVSA1011413 150223197532 F45000 8998 1 M 898809 ME3799090 0612199523 1 5 G NY2 0 ENGINEER
PCMNSA1011415 15040155D5W6904106 2026 SA1011411 1201200501052007365 2 12 SP78912 12 1202200512252006I D5W6904106 I10 new policy D0 328 0 8800
If the fixed width file has less number of fields compared to the actual schema definition you can go to the Advanced properties of the Adv Positional Schema object and enable 'Allow less fields'.
Similarly if the actual data file has more fields than the ones defined in the the Positional Schema then check the 'Allow more fields' property.