Start from the one who matters the most to you and your values.
If the criteria becomes white only, let it be.
Discussion
It would never be only white.
The main criterais are :
Married with children
Sharing my values
When that time comes, I think you and your wife will know who to help. Maybe different ones in different ways.
It's a powerful thing when you see resources as tools to bless others. Sounds like a great thing to pray about!