Postman - Aggregating or inculding tests

I have a question about Postman, collections and aggregating them.

My project have a lot of Postman tests, how are already in many collections. For example, collection.A has 30 tests, collection.B has 45 tests, and so on.... To simpify the test execution, I would like to create a single collection that will call collections containing single tests. So it will be possible to run all tests in a single call.

For example:

Collection -calls--> Collection.A -has---> Test.A1, Test.A2...
                 I-> Collection.B -has---> Test.B1, Test.B2...
                 I-> Collection.C -has---> Test.C1, Test.C2...

Is it possible and how ?

So, I don't want to regroup all single tests in only one collection. Each collection must be executed separately...

Thanks in advance for yours tips.

Sony