Since 2001, the National Institutes of Health (NIH) have funded the Institutional Development Award (IDeA) Network of Biomedical Research Excellence (INBRE) to expand biomedical research capacity among states in which NIH funding was historically low. The Western IDeA Region comprises seven states: Alaska, Hawaii, Idaho, Montana, New Mexico, Nevada, and Wyoming. Beginning in 2017, these states developed an interstate "supernetwork": the Regional Alliance of INBRE Networks (RAIN). RAIN's four initiatives are: 1) holding regular INBRE program director/principal investigator (PD/PI) communication and strategy sessions; 2) sharing research Core Facilities and programs; 3) developing interstate undergraduate student research exchanges; and 4) promoting interstate research collaborations. The seven INBRE PD/PIs meet monthly, usually virtually, to share administrative best practices, help each other problem-solve, and support one another's competitive renewals. Sharing IDeA-built Core Facilities and programs offers unique and/or faster services for researchers, without states needing to duplicate core capabilities. This substantially reduced costs. In 2019, ID-, MT-, and NM-INBREs estimated that sharing their existing Core Facilities and services saved $27.6 million over the course of one 5-yr funding cycle. Each undergraduate summer research program is open to other RAIN state students, with 29 student participants thus far. Faculty interdisciplinary research is promoted by a Collaboration Studio and special funding. To date, RAIN support has led to 18 scientific presentations, 12 peer-reviewed publications, and generated $1,400,000 in new NIH grants. RAIN is a model for other programs to share best practices, enhance interdisciplinary collaborations, limit redundant infrastructure, and share research/mentoring expertise.