If there is more than one person entitled to maintenance and if the person liable for maintenance is incapable of paying maintenance to all, the following order of priority applies:
1. minor children and children within the meaning of section 1603 (2) sentence 2,
2. parents who are entitled to maintenance for the care of a child, or would be so entitled in the case of a divorce, and spouses and divorced spouses in the case of a long marriage; if it is determined that the marriage was long, account also is to be taken of disadvantages within the meaning of section 1578b (1) sentences 2 and 3
3. spouses and divorced spouses who do not fall under no. 2,
4. children who do not fall under no. 1,
5. grandchildren and more distant descendants,
6. parents,
7. further ascendants; among these, the more closely related take precedence over the more distantly related.