This is what the searchAfter parameter is for.  The FindLine method has several overloads with various options. Basically, you'd start with the simplest one and locate the first line. Then you can use the overloaded method with the search After parameter and pass it the result line from the previous find (and so on and so forth). The searchAfter parameter will resume searching but start from the line that is passed in; essentially allowing you to daisy-chain them together.