Am I right in reading this as though you have 3 groups of 4 panels in series and all three groups are feeding in parallel to a common line . Also you have groups not seeing the sun at the same time.
If so it should work, it won't work if sun is not on all series panel at one time.
With the drastic shading between groups, make sure the series blocking diodes are capable of blocking the voltage of the 4 panel strings . If not, include a good high voltage blocking diode in each string.
Flux