Mandatory field on the Kb article

Hello to all,

I have a customer need
On the kb_knowledge_base.list table I have created a custo field (u_mandatory_ownership_group) of type (true /false)
When creating a knowledge base Kb, if this field is checked to true, make the field ownership group (ownership_group) which is on the table of articles: kb_knowledge.do to mandatory and if it is not checked to true, do not make it mandatory.
Attached are the screen shots of the two tables
Thank you for any suggestions.

Regards

Midro