Can an Investor 1031 exchange out of property held in one Title Holding Trust and buy property held in a different Title Holding Trust?

Yes, as long as the underlying beneficiaries of both Title Holding Trusts are exactly the same the transaction will qualify for tax-deferred exchange treatment under Section 1031 of the Internal Revenue Code. Both properties do not need to be held in a Title Holding Trust. You could sell Relinquished Property, that was held in a Title Holding Trust, and acquire Replacement Property, that is held in your individual name as long as the individual was also the beneficiary under the Title Holding Trust.