This is one of the most common questions. It will save you time if you perform some research before asking. Any way, review this document: How to-Master Data Governance for Material: BADI USMD_SSW_RULE_CONTEXT_PREPARE to Enhance User Determination which addresses your exact question.
Also, for any future MDG questions, please take a look first at this document Configuration and Enhancement of SAP Master Data Governance as it contains many of the commonly required enhancements.