A couple of ways come to mind. You can send multiple insert statements in one SQL script or batch from your WEB APP.
Insert table1 (col1, col2, col3, col4)
Values (val1, val2, val3, val4)
Insert table2 (col1, col2) Values (val1, val2)
Insert table3 (col3, col4) Values (val3, val4)
Or you can create a trigger on a table that would do the inserts in the other table(s) when a new record is inserted.
Create Trigger trgInsert On Table1 For Insert As
Set Nocount On
Insert table2 Select col1, col2 From Inserted
Insert table3 Select col3, col4 From Inserted Terry
"The greatest obstacle to discovery is not ignorance -- it is the illusion of knowledge." - Daniel J Boorstin