Pulling Protien Genbank files and All of it's isoforms from NCBI

Question

[hakimelakhrass]

I have an R script that can take a list of proteins and returns you all of the genebank files. I am having trouble expanding that script to also include the isoforms of a protein. The only solution I can think of is pretty dirty. As of now my script returns exactly one genebank file for every protein name. I achieve this by putting a constraint on the number of returns to 1. My idea was to now allow say 50 files to return and then grep for the isoform and protein name. I was wondering if anybody knows of a cleaner solution. Thanks!