In determining the resources of an individual (and spouse, if any) who is of Indian descent from a federally recognized Indian tribe, we will exclude any interest of the individual (or spouse, if any) in land which is held in trust by the United States for an individual Indian or tribe, or which is held by an individual Indian or tribe and which can only be sold, transferred, or otherwise disposed of with the approval of other individuals, his or her tribe, or an agency of the Federal Government.