Need To Replicate Sales Info To Head Office

Here's My scenario,

I am using SQL2k5 with sp2. In have three branch stores in my site each with SQL 2k5 and a master server at headoffice also with SQL 2k5. The sales transactions for each store goes to a table called sales transaction. What I need is that the info from the sales transaction of each branch populate the sales transaction table at the head office, but not vice versa. That is to say the sales transaction table at each branch must have their information alone and no information from any other branch. Only the head office must have sales transactions from all branches in it's table. What type of replication do i use and how do i implement it?

Muchas muchas gracias.