SQL Server Express Edition Primary - Secondary Model
An answer to Replication from one SQL Server Express to another on Stack Overflow offers some suggestions:

In summary (from the link):


Write an application that transfers "articles" from your "publisher" db to your "subscriber" db(s).


OR


Create a set of views to have a summation of data that you want to be
published. Then create INSTEAD OF triggers on these views (you can't
create an AFTER/FOR trigger on a view) to process that data and
transfer it to your "subscriber"(s).


Triggers On Views? What For? by Michael J Swart has some good information on view triggers.