Theres no way to 'counter' fuego's.. I believe that the same way the devs intended Gordos and RPG's go together so WELL, is the exact same way that the devs intended for fuegos and compounds to go together. I have no doubt that no other kind of troop on the game could do as much damage to a compound as fuego's.
The best way to counter the fuego effect on your compound? Win your wars by having the best members you can have, do as Maniak said.. first, and most importantly.. make sure your cartel members have the tools to win the wars (extra energy / sics etc.) and then focus on making your compound solid
In MOST cases, if not all, the compound very rarely becomes the deciding factor in a war, what decides the war is who has the better attackers - but it can certainly suck to lose a war because you had to use one or 2 more attacks on the compound than the other cartel