Meaning of "Gruppe 1 C"

[Mario Satta]

I am researching the backgrounds of a particular airfight occurred on May,25,1944 over "Piacenza/S.Damiano Airport"
(In that airfight - flying a Macchi C 205V fighter - lost his life a close relative of mine, Ten. Pil. Vittorio Satta).
In the course of my research I came across the terms: "Gruppe ic", that should refer to a Unit - or Organisation - direcly or indirectly related to "Schlacht Geschwader 4" (then using Piacenza Airport as its main Logistical Base) in its attempt (operating from many smaller airports and tactical "strips" much nearer than Piacenza to the frontline) to stop the Allied Armies' advance up the Italian Peninsula after the Salerno Landings.
- - - Can any member of tis excellent Forum explain me what "Gruppe ic" does mean?........
Wandering on the net i found out that
1) - the "Gruppe ic" I am speaking of kept a "Kriegstagebuch";
2) - the term "Gruppe ic" is still referred to in today's Germany.
Thanks in advance to whomever will help..... M. Satta