How can I create a matrix of scatterplots that summarize interactions between two sets of variables?

Question

I have two sets of variables, one of environmental data, and one of response data. I want to make a matrix of scatterplots that shows how each of my response variables interacts with each of my environmental variables.

I have tried adapting the ggally package's ggpairs() function, but it seems to only work within one set of variables, showing the correlation between all combinations of variables. I am not interested in how each of my response variables correlates with each other or how my environmental variables correlate with each other. Showing this extra information would not be an issue, except that I have many more environmental variables than response variables, so if I create a symmetrical correlogram, my environmental variables dominate the figure and make it difficult to read. I could possibly remove columns and rows of the matrix of plots to create a figure with only one set of variables on either larger axis, but cannot find any way to 'crop' the correlogram this function creates.

Is there some way to adapt ggpairs() to my needs? Or is there another function that would better suit my purposes?