Mandated Income - Rent of Property to Residual Beneficiaries

A deceased mother in her will leaves her private residence to Trust with Right to Occupy for Life to a Son (no 1). Son No 1 to Pay Full Value Rent. Trust Beneficiaries are Residual Beneficiaries of her Will. They are Son 1, Son 2 and Daughter Equally.
Can the Rental Income be mandated to all three Children? How would that work with Son 1?