Complex sentence: Since that time AICSA has worked to support the IVCFs and it's member choirs in their activities-it has offered this support as an advisory body for it's members, and as a national face for the Australian Intervarsity Choral Movement.
Split into simpler sentences: Since that time AICSA has worked to support the IVCFs and its member choirs in their activities. It has offered this support as an advisory body for its members, and as a national face for the Australian intervarsity choral movement.