Six strings that are for some reason important

  A -> a b c a b c

  B -> a b a b c a

  C -> a b c

  D -> b c a

  E -> b c a b

  F -> b c b a

Those strings could potentially be very long.

I want to find every occurrence of every of them is a potentially very long string

Such as: 

  b a b c a b a b c a b c x b c a b k a b a b c b a c b


C appears between input positions 1 and 3
D appears between input positions 2 and 4
E appears between input positions 2 and 5
C appears between input positions 6 and 8
B appears between input positions 4 and 9
D appears between input positions 7 and 9
E appears between input positions 7 and 10
A appears between input positions 6 and 11
C appears between input positions 9 and 11
D appears between input positions 13 and 15
E appears between input positions 13 and 16
C appears between input positions 20 and 22
F appears between input positions 21 and 24


Verifying:

  0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
  b a b c a b a b c a  b  c  x  b  c  a  b  k  a  b  a  b  c  b  a  c  b


C appears between input positions 1 and 3
C -> a b c
  
  1 2 3
  a b c


D appears between input positions 2 and 4
D -> b c a

  2 3 4
  b c a


E appears between input positions 2 and 5
E -> b c a b

  2 3 4 5
  b c a b


C appears between input positions 6 and 8
C -> a b c

  6 7 8 
  a b c 


B appears between input positions 4 and 9
B -> a b a b c a

  4 5 6 7 8 9
  a b a b c a


D appears between input positions 7 and 9
D -> b c a

  7 8 9
  b c a


E appears between input positions 7 and 10
E -> b c a b

  7 8 9 10
  b c a  b


A appears between input positions 6 and 11
A -> a b c a b c

  6 7 8 9 10 11
  a b c a  b  c


C appears between input positions 9 and 11
C -> a b c

  9 10 11
  a  b  c


D appears between input positions 13 and 15
D -> b c a

  13 14 15
   b  c  a


E appears between input positions 13 and 16
E -> b c a b

  13 14 15 16
   b  c  a  b


C appears between input positions 20 and 22
C -> a b c

  20 21 22
   a  b  c


F appears between input positions 21 and 24
F -> b c b a

  21 22 23 24
   b  c  b  a