how to get found set with script based on another list value
I have a table that have all customer POS recorder, and I have another table that have some key customer list , the key cusotmer list only have the customer name keyword.
I want to get some recorder set that including all key account POS from POS list accoridng to key cusotmer list key word name.
I have the following script , that can work with find mode, but it show a customer POS, not show all key cusotmer POS list.
do you know how to change the script to get what I want.
go to layout ["POS_list"(POS)]
go to layout["assigncustomername"(Assigncustomername)]
go to record/request/page [next;exit after last]
set varible [$$assign;value:assigncustomre::Customer_POS_name]
go to layout ["pos_list" (POS)]
show all records
enter find mode
constrain found set 
actually, I want to let constrain found set can filter all key account list.