It would be so effective to have a relationship field be able to link 2-way. This would allow a seamless relationship between two tasks under the same relationship type. Right now, we can add the same relationship custom field into two different locations, however, when adding a relationship, from one task into another, where you add the relationship will sit in that custom relationship field, but in the linked task, it'll show as "Reference".
If the same custom field relationship is in each list, and two tasks are added with a relationship together, my thoughts are we should have the ability to show it as a two-way relationship. Organizationally, this would be exceptional.