if i have table in database(sql server) and has 1500 records and i run 2 applications(at same time) that will retrieve 500 records each so how can i do this

app1 will retrieve first 500 records
app2 will retrieve next 500 records means no over lap

SET Transaction Isolation Level Read committed not working for me

note: actually my app have one db and many client apps so (running 1 or more at a time) while reading records from DB i have to lock those rows so that it can't be read by others' requests and after that i will update status. question is how can i LOCK rows while reading ?