Person Selection Rule using GET_VALUE_SET - how to return more than 1 record?

Summary: GET_VALUE_SET function only returns the first record of the given value set. Does anyone know of a way of returning MULTIPLE records, ie a list of employees to the Person Selection formula.

Content (required): I need to use a Person Selection Rule to find all employees with an open-ended Sickness absence. If i use a SQL (table-validated) value set to find the employees with open sickness absence, and then use GET_VALUE_SET function call in the Person Selection Rule formula, the GET_VALUE_SET function only passes back the first record. I need it to pass back ALL employees with an open-ended Sickness absence to the Person Selection Rule formula. Does anyone know how to do this? Are there alternatives to using a table-validated value set to do this? Thanks