Changing the set of values in one custom field depending on selected value

[Meenakshi]

I have a custom field A of type multi-select. And there is another custom field B of type multi-select. I want that on selecting a value of custom field A , the set of values to choose from the custom field B gets modified. Is there a way to do that?

I am using JIRA v7.0 and cannot find the Multi-Level Cascading Select plugin in it. 

[Nic Brough -Adaptavist-]

When you say you're using JIRA 7, do you mean Early Access (not suitable for production use) or Cloud (where you can't install that addon anyway)?  As far as I can tell, the add-on has not been updated for version 7 anyway, so you'll have to wait until it is.