How to give unque number to every different group of numbers ?

create table #parts
     (
     PartNumber varchar(50),
     PartValue int,
     UniqueNumber int
     )
     insert into #parts(PartNumber,PartValue,UniqueNumber)
     values
     ('P1',1,NULL),
     ('P1',2,NULL),
     ('P1',3,NULL),
     ('P1',4,NULL),
     ('P2',1,NULL),
     ('P2',2,NULL),
     ('P3',1,NULL),
     ('P3',2,NULL),
     ('P3',3,NULL),
     ('P4',1,NULL),
     ('P4',2,NULL),
     ('P4',3,NULL),
     ('P5',1,NULL),
     ('P5',2,NULL)

expected result as below

PartNumber	PartValue	UniqueNumber
P1	1	1
P1	2	1
P1	3	1
P1	4	1
P2	1	2
P2	2	2
P3	1	3
P3	2	3
P3	3	3
P4	1	3
P4	2	3
P4	3	3
P5	1	2
P5	2	2

SELECT
   p.PartNumber,
   p.PartValue,
   p2.Parts,
   NewUniqueNumber = DENSE_RANK() OVER (ORDER BY p2.Parts)
 FROM #parts p
 JOIN (
     SELECT
       p2.PartNumber,
       STRING_AGG(p2.PartValue, ',') WITHIN GROUP (ORDER BY p2.PartValue) Parts
     FROM #parts p2
     GROUP BY
       p2.PartNumber
 ) p2 ON p2.PartNumber = p.PartNumber;