Function similar to subsindex for cell?

I'm working on pulling names out of an excel document that received a certain product lot number. I've written a function to pull out the correct lot numbers, however I want to be able to create a smaller matrix of only names that are associated with 5 or so lots. I know how to write this function for non-cell data or for finding names associated with a single lot, however I can't figure out how to pull out multiple names. What would be the best way to pull out names matching single elements from a list such as:

    []
    'xxxxx2'
    'xxxxx3'
    'xxxxx4'
    []
    'xxxxx6'
    []
    'xxxxx8'
    []

from a relatively large matrix?