(See the best response by Lummox JR.)
Is it possible to add subscription for my hub? ExcelRayneCECustomEdition

I tried an alternative solution using a game that already has a hub, here:

However they get error when trying to purchase

"X was unable to make a purchase for the hub entry Mistamage123.RpRadioCE. The call to PayPal failed with error code 580001. The error message was: Invalid request: Unilateral payment is deprecated"

Is it possible ?
Best response
You don't have a PayPal email set up for the second hub entry; that's why subs are failing.

I've moved your new entry to Published so subs will be active, but you'll need to set a PayPal email for that as well.