关于SMU MQF referee的问题

lesonlonUID: 3858429

网站上面提到：
Of the two personal references, one should typically be from a current or previous employer, a colleague, or someone else who knows you well at work; the other referee could be someone who taught you at university or college, or another person who knows you in a professional capacity.
第一个要求是不能是学校的老师，因为我没有这方面的人能作为referee，所以想请问一下申请的同学，这个要求是必须的吗，还是说可以放松到2个referee都是老师？