Autocomplete rule on two business objects

Summary: Can I write a rule on a business object based on another business object's attribute or based on two business objects? 

Content (required):

there are name titles that are dedicated to only one gender type(example: 'Mr.' for Male) so we want to default the title based on the gender provided using Autocomplete but the business object for Gender is 'Person legislative information' and Title is under 'Person Name' business object how can I use those two business objects in one rule.

Version (include the version you are using, if applicable):

21D

Code Snippet (add any code snippets that support your topic, if applicable):