I have list integer field in 3 content types and each have same possible values (from 1 to 6) and I need to disable user to choose the same number for two nodes, so each node with this field filled in need to be unique.
I found Unique field module but it is not working for me, because I have field in each content type and I need to look at all nodes from all content types and this module is on content type base.
Basic example of what I need:
Field field_1 from content type type_1 have value 5, so field_2 from content type type_2 and field_3 from content type type_3 can't have value 5.
Any idea how to achieve this?