After u get the list of the targets, for every target create a URL connection and set all the form paramters in the URL Connection object and do the submit to the target.
May be u can use this helper class from Servlets.com. Actually u can implement this by urself but anyways this might help in making the HTTP related GET, POST kind of requests without having to understand URL, URLConnection etc..
U can also do this from the client side ...
Have a dummy frame (Hidden frame with size 1,1) and have a dummy form with all the form parameters in HIDDEN tags.
When the user submits the actual form, loop through all the targets and update the hidden frame's form with the actual form values and set the proper target and submit. After some delay, load the hidden frame again with the initial dummy hidden form page, and do the same operation till u finish all the targets.
There are so many other ways u can do this ... doesn't necessarily have to be a hidden frame ...