This type of harmony can be within a single diatonic scale e.g. C or 3 diatonic scales in harmonic relations e.g. G C F
The harmonic triplets of chords per mode are the next
Diatonic harmonic triads
(Xn)m->(Xn+1)M->(Xn+2)M (e.g. 2m7->5M->1M) Myxolidian harmonic triad
(Xn)m->(Xn+1)m->(Xn+2)m (e.g. 3m7->6m->2m) Aeolian harmonic triad
(Xn)M->(Xn+1)M->(Xn+2)M (e.g. 5M7->1M->4M) Ionian harmonic triad
All of them are the next
1. IONIAN : HARMONIC TRIPLET (5M, 1M, 4M)
2. DORIAN : HARMONIC TRIPLET (6m, 2m, 5M)
3. PHRYGIAN : HARMONIC TRIPLET (7d, 3m, 6m)
4. LYDIAN: (SEMI) HARMONIC TRIPLET (1M, 4M, 7d)
5. MIXOLYDIAN: HARMONIC TRIPLET (2m,5M, 1M)
6. AEOLIAN: HARMONIC TRIPLET (3m,6m, 2m)
7. LOCRIAN: (SEMI) HARMONIC TRIPLET (4M, 7d, 3m)
E.g. in a single diatonic scale
1) Phrygian, Aeolian Dorian resolving to Ionian
2) Phrygian, Aeolian Dorian resolving to Mixolydian
3) Aeolina, Dorian Mixolydian resolving to Ionian
Or in 2 diatonic scales in harmonic relation e.g. G C F
1) Phrygian of G, Phrygian of C , Phrygian of F resolving to Ionian of C
2) Aeolian of G, Aeolina of C , Aeolina of F resolving to Ionian of C
3) Dorian of G, Dorian of C , Dorian of F resolving to Ionian of C
4) Mixolydian of G, Mixolydian of C , Mixolydianof F resolving to Ionian of C
