As far as I understand you have shared line configuration, so yes all the phones will ring if number and partition are the same
If you don't want this you must give each phone a different number and then you can use line groups to distribute calls
1) With Same number on multiple phones it will ring all the phone.
2) You have to use the Hunt Group Feature to solve the issue.
You will assign different number to all phone say 2001,2002,2003 etc & Define one Pilot Number say 2222.
Configure line Group with all DNs as members and Ring strategy as Broadcast, Hunt Group and Hunt Pilot with 2222 as pilot number. So once 2222 is dialed all phone will ring. If you dial individual numbers say 2001 one specific phone will ring.
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