Is is legal for a Kansas nursing home to send a medication to the hospital with a resident?

if the hospital doesn't have the med on formulary. We have all but one nursing home that will work with our hospital when a resident is admitted. One NH here says it's illegal to send the resident's med with them for their stay in the hospital even though we don't keep in on formulary. That's clearly not what's best for the patient and I find it hard to believe it's illegal when our other nursing homes are very helpful in this matter.