Custom Field options based on project. Field should show different options based on the project

[Shaikh Arif Mohd Mondal]

I have two projects "ABC" & "DEF". There is a common field ( Drop down list) "Activity Type" in both the projects. But I want this field should show different options in two different projects. For for project ABC it should show- m,n,o,p options and for DEF it should show x,y,z options. So that the options of ABC project wont interfere in DEF. Is this possible, If yes. instructions

[Joe Pitt]

You can do this with context. You can do it by project or issue type. copy/paste: 

https://confluence.atlassian.com/adminjiracloud/configuring-a-custom-field-776636423.html  

Just clicking the link sometimes appends text that makes it fail.