Allegation of assault against a student at one university by students at a second university does not state a Title IX claim against the second university where the alleged victim has not and does not intend to avail himself or herself of the educational programs and services of the second university.
http://media.ca1.uscourts.gov/pdf.opinions/17-1941P-01A.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.