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The short answer is "yes," but I'd feel better knowing a little bit more about your configuration.
If you are doing the "typical" rabbit-hole configuration to bring in a Telco PRI, and then convert that to an RBS T1 doing Feature Group D, mapped to FXS ports, which then connect to an alarm receiver then the existing rabbit-hole will work for as many PRIs as you can connect to the ATLAS. The "IN#ACCEPT" for the USER TERM T1 is used for accepting the call, and you have a bandwidth limit of the T1 and however many FXS ports are mapped to it. So with 1 T1 mapped to 24 FXS ports, you are limited to 24 calls at one time, however with 2 PRIs there can be 46 calls coming into the ATLAS (if all the channels were active at the same time). If all 24 FXS ports are active, any additional calls on either PRI will get a BUSY.
If you are adding a Dual T1 card, then you do not have a rabbit-hole with 24 FXS ports, because that would take up all of the available USER slots in the chassis, but the theory is still the same.
Hope this helps,