ReadyApi - form-data values

POST -request - how to set several form-data values using the same name ?
for example we should set:

property_set ->object_name=API testing

property_set -> subject=test

property_set -> country_code=FI

if I use 
Multi-Value Delimeter = ;

and set the values as follows into the request

Name -> property_set

Value -> subject=object_name=API testing;subject=test;country_code=FI

it won't work. 

from postman the log is as follows for every property_set 

----WebKitFormBoundaryxxxxxx
Content-Disposition: form-data; name="property_set"

object_name=API testing

----WebKitFormBoundaryxxxxxx
Content-Disposition: form-data; name="property_set"

subject=test