Field type Entity Reference as select list but based on value

Question

I want field with entity reference showed as select but based on value from the another field in the same form [radio button field] for example the entity reference field will list these values

-entity 1
-entity 2
-entity 3
-entity 4

and the field radio button will hold countries like so:

-England
-Germany

notice that the entities reference (Content Type) has field called country, so when i check the value "England" i want the field entity to be filtered based on England for ex: -entity 1 & -entity 4 and same if i clicked Germany.

is that applicable in Drupal 7 even by Views module, or i have to do it custom !?

Answer 1

You can use Dynamic dependent fields module.

Project page says:

Makes field value or options depend on other field values when editing entity.

Answer 2

i think it is done by Conditional Fields see tutorial here