Search Builder criteria for a Multi-select field value

[phlyshaq]

Our CiviCRM is full of teacher records. We use a custom data set to handle the 'Grade' these teachers are interested in. Values range from K-12, and in practice, every imaginable combination of options is selected (e.g. "K-2", "6-8", "4", "K, 3, 9")

Search Builder is the only way to even come close to setting up the SmartGroups I want, but even it is lacking.

For example, I want to create a group of people who entered just "K" or just "1" or "K,1". But I want to exclude anyone who might have selected "K-2", "1-8", etc.

The only-K and only-1 terms are simple, but for the life of me I can find no operator to bring up contacts who've selected "K,1". When I try Contact, Grade = K, 1 no results come up, even though I know such records exist. Any ideas?