How to deliver 2 types of customers (2 NAS) through one switch ?

For example, we have 2 NAS = Fiber NAS , Wireless NAS.
Both are Microtik 1072.
Now, I have 21 POP in a radius of 100km.
Each POP is connected in a ring fiber network of single core. Only one single core which is connected to the DC managed switch.
Each POP as one managed and unmanaged switch for access network to connect to customers.

And all of our customers are authenticated by PPPoE.
Now, what I want is,
any customer we connect those POP’s unmanaged switch, be its a wireless customer or fiber customer, their request and authentication should go to the dedicated NAS router.


For example, if a POP A building has 2 customers. One needs a wireless plan and one needs a fiber plan, then we connect 2 ports from unmanaged switch to both the customers.
and enter their PPPoE credentials.

Now, I want is, the wireless customer PPPoE session should be created in WIRELESS NAS ROUTER.
I want is, the fiber customer PPPoE session should be created in FIBER NAS ROUTER.

So, how to do that ?

I guess, we have to connect a cable from both fiber NAS and wireless NAS to the DC managed switch which goes to the POPs. But how will the POP switch ports know and throw the session to the specific routers ?