Hi,
Create an object in Flex Side (var temp:Object=new Object()) and assign the values whatever are required for you to this Object
for example:
temp.Company Name="XXXX";
temp.Addr1="XXXX"; and so on...............
In the same way collect all th list of Users to one Array and assing the same array to the Object
temp.users=arr;
And send this object(temp) to the Php via HttpService.
I dont know how to get in php but in java you can use request.getParmaterValues("users") in order to get users that you are sending