Storing vectors as vectors and iterating through them

Hi all,

I have a bunch of int vectors. Each vector holds a bunch of ints that 
correspond to row numbers of an existing matrix. I use the int vectors to 
pull out rows of data from a matrix, i.e.

data <- my_matrix[int_vector,]

I would like to store these int vectors in some sort of data structure that 
will preserve them as-is and allow iteration. I guess what I'm looking for 
would be something analogous to the java Vector class, as in this java-like 
pseudocode :

Vector V = new Vector;
V.add(a,b,c) // where a,b,c are lists

for(int i = 0; i<V.size; i++)
{
    List L = (List)Vector.get(i);
    plot(L);
}

The point is to iterate through the data structure containing the int 
vectors, and, for each int vector, do some clustering and plotting, but what 
I cannot find is a data structure in R that would support this.. trying 
c(a,b,c) does not preserve each int vector, but instead merges all the ints 
into one vector. I need to keep them separate (so I can create a separate 
plot for each vector).

Thanks in advance,
Ken