Alright thanks for clarification.
So I would have to create some kind of approach then to uniquely tag the products with an identifier and then link them with the actual "one video" that needs to be played. I'm thinking about something like the following.
For example, the identifier I choose is "abc", now for monthly item, I can tag this item as "abc_m" and for yearly "abc_y". The original item, the video that has this subscription attached to, will have something attached to it which would be "abc". So, I can add _m or _y and then check in the collection returned by GetPurchases() function if it has any one of those variations. I think it makes sense now, isn't it?