How can I use a Powershell script to output data for an Invoice

Input Data, in a file called Source.txt

ISA*00*          *00*          *12*1234567891     *ZZ*COMPANYCOL     *213456*1234*A*00123*123000010*1*P*>~
GS*IN*2134567891*1234567891*20141024*1234*00*X*001234~
ST*999*1234561~
BIG*20141020*123456.*20140917*1234567.~
N1*RI*COMPANY*0*000000000~
N1*BT*COMPANY 2*0*12345678910000~
ITD*00*2*****00~
DTM*000*20141020~
FOB*CC~
IT1*1*200*CA*5.4**UN*123456789123*VN*01234A~
IT1*2*50*CA*1.4**UN*213456789122*VN*02345A~
IT1*3*60*CA*12.4**UN*789456123123*VN*06789A~
TDS*1234567~
ISS*1234*CA*12345*LB~
SE*12*123456~
GE*1*10~
IEA*1*123000010~


For each ISA to IEA data set in file, and there could be several, I would like the following
desired Output Data, in a file called Output.txt:

Company:  COMPANYCOL  (these are the words next found next to ZZ)
Type of document:  999  (these are the numbers next to the ST)
Identifier: 123000010  (the number found in IEA)

Then below the above output, I would like a blank line, and then I would like the data from the Source.txt to be displayed underneath it.

So the Output.txt file should look something like this, in this case:

Company:  COMPANYCOL
Type of document:  999
Identifier: 123000010


ISA*00*          *00*          *12*1234567891     *ZZ*COMPANYCOL     *213456*1234*A*00123*123000010*1*P*>~
GS*IN*2134567891*1234567891*20141024*1234*00*X*001234~
ST*999*1234561~
BIG*20141020*123456.*20140917*1234567.~
N1*RI*COMPANY*0*000000000~
N1*BT*COMPANY 2*0*12345678910000~
ITD*00*2*****00~
DTM*000*20141020~
FOB*CC~
IT1*1*200*CA*5.4**UN*123456789123*VN*01234A~
IT1*2*50*CA*1.4**UN*213456789122*VN*02345A~
IT1*3*60*CA*12.4**UN*789456123123*VN*06789A~
TDS*1234567~
ISS*1234*CA*12345*LB~
SE*12*123456~
GE*1*10~
IEA*1*123000010~