Need to display 1 real estate listing on 100 other sites I own

Here's my challenge - I need to be able to input a real estate listing in one place and have it displayed on over 100 separate word press websites - all of which I own.

I have a main real estate web site but I need to display the listings on all 100 separate sites but do not want to have to re input the listing over and over.

Any ideas?