Each has its own APN??
This part is not clear
you query is not clear
Let me tell you how it will work.
For every dedicated bearer there will a packet-filter associated to it.
If the dedicated bearer is GBR bearer. Then it will have a Guaranteed-Bandwidth associated with it along with Maximum Bandwidth.
For Eg Ded Bearer 1 has 2 filters, 1 uplink and 1 downlink with GBR 500kbps and MBR 600kbps
So, the data flow rate should be atleast 500kbps but should not exceed 600kbps
Now, let's consider a case of Non-GBR bearer
In this case every filter will have a Max-Bandwidth associated with it.
Eg: Dedicated Bearer 2 has 2 filters, 1 uplink and 1 downlink. MBR for the fitler is 500kbps.
So that filter can use bandwidth from 1kbps to 500kbps however it cannot exceed it.
There is one more term to consider in case of non-gbr bearers. APN-AMBR
This bandwidth is shared among all filters of non-gbr bearers
Eg: APN-AMBR for a bearer is 1000kbps
now let's say you have 10 filters which are part of non-gbr bearer and each has 150kbps max bandwidth. So, now PGW has to ensure that all of them together should not consume bandwidth over 1000kbps.
Hope this helped