STUCK : String Comaparison

I may be just over thinking this but I'm stuck trying to figure out a solution that has to deal with comparing a series of dynamic strings to a known string. The strings will be 8 characters long and each character will be either a zero or a 1. What I need to do is to compare the dynamic strings with the known and if each of the 1 characters in the dynamic string aligns with the 1 characters in the known string it will throw a flag. The dynamic string does NOT need to contain all of the 1 characters that the known string does, just that the ones that it contains align. Examples: Known: 10100010 Dynamic: 00100000 Throws flag because both strings contain a 1 in position 3 01100000 Doesn't throw flag because there is a 1 in position 2 10100000 Throws a flag because the 1s in position 1 and 3 align 10110000 Doesn't throw a flag because of the 1 in position 4 I was able to create a function that matches the entire string but I lost it when trying to deal with partial matches. Does anyone have a potential solution for such a beast? I appreciate any input you might be able to offer... Thanks, Ron