Are you planning to collaborate on research with colleagues from another institution who already have IRB approval? If so, there is an option in Mentor to submit a proposal reviewed by an external IRB. You will need to upload a copy of the approval letter from the external IRB, along with the approved protocol and all accompanying documents (consent, recruitment, instruments, debriefing, etc.).
In some cases, the HPRB may choose to approve a reliance agreement, indicating that we will cede oversight of the research to the other IRB. This is done at the discretion of the HPRB. See a sample reliance agreement here.