I need help with something similar, what if start1 and end1 happens more than 1 time?

start
bla bla bla1
start1
bla bla bla2
bla bla bla3
end1
bla bla bla4
bla bla bla5
start2
bla bla bla6
bla bla bla7
end2
bla bla bla8
start1
bla bla bla9
bla bla bla10
end1
end


how can I get those lines too?...