Relationship Issue

I have a heck of a time getting my mind around this relationship, fumbling around every time with it.

In the Parent Table – Resets, I use a text-formula field in the Resets Table to create the ResetID#, this ResetID# is then passed to the Child Table – Travel, when a new travel record is created for a given reset. A reset can have one travel record or innumerable travels.

Now what I want to do is reverse the order, where the Travel becomes the Parent Table and Resets becomes the Child Table. What I need is to pull back to the Reset Table the associate that is the assigned Lead for a Reset (Reset Lead). Of course, the common denominator is the ResetID# in both tables. The ResetID# is not the key field in either table. So, how can I make this field a relate-able field in both tables?