Different structures in one array, how?

[XfoxX]

I've 7 structures. Smallest structure has 2 variables and largest 8.

struct invA_typ { // smallest struct
long A;
long B;
}

struct invG_typ { // largest struct
long A;
...
long G;
}

I've to deal with all the structs as one array to loop trough them, how can I do that?

Thanks in advance