How to then pass just one field back to the multi-form

[ThiepLV]

Hi guys
In cookbbook i read as follows:

What if you need to pass just one field to a multi-form, such as a facilityId?  One way (maybe not the best way!) is to put into the form target URL, like this:
target="BatchScheduleShipmentRouteSegments?facilityId=${facilityId}"

However i don't would like put into the form target URL.

Can someone help me?
Thank you for your help!