Joe Petito, Gabby's father, tells TMZ ... national media coverage played a big role in his daughter's case, but he knows not everyone has that same benefit. Joe says every missing person deserves the same attention as Gabby, and that's why they're pushing for expanded use of the government program, NamUs.

NamUs is a national information resource center for missing, unidentified, and unclaimed people in the United States. The Department of Justice-funded program provides technology, forensic services and investigative support to resolve missing person and unidentified remains cases.

Currently eleven states must participate in NamUs, but all U.S. states can voluntarily participate.

Two months ago, Gabby's parents broke out a list of U.S. senators, and started calling all of them to muster support for expanding access to NamUs. Joe says they were overwhelmed by the wave of positive responses after getting through just half the list, and he adds ... they got the same reaction when they reached out to governors' offices.

Now, the family is speaking with policy teams for veteran Senators Elizabeth Warren, Ted Cruz and Dianne Feinstein ... just to name a few. So far, everyone seems open to creating legislation that includes NamUs, but Gabby's family won't be satisfied until bills are introduced federally and in every state.

Joe emphasizes this is not meant to be a partisan issue ... but something all Americans should rally around. More than 4 thousand unidentified remains are recovered every year, which hits home for him, as 7 bodies were discovered just during the search for Gabby.

As you'll recall, Gabby went missing on a road trip with her boyfriend Brian Laundrie. After a nationwide search and constant media coverage, Gabby's body was found in Wyoming a week after being reported missing.