Either awk or a script may be better suited for what you want to do. If you want to do something like filter lines with yes in one file and line with no in another, then the program sed would suffice. Awk would be better if your file is organized into columns and fields.
As an answer to your question however, you can check for more then one pattern like this:
grep -e pattern1 -e pattern2 ...
I will sometimes use grep to filter out the very long results of the locate command.
grep -v -e pattern1 -e pattern2 ...
I would add a new pattern that I'm not interested in until the listing is small enough to find the pattern I'm looking for. By the way, the -v option inverts the result of grep and eliminates patterns with the line.