Display only duplicates from a 2D array

I have been trying to use Split and Filter to display ONLY the duplicate zip codes within a column list of zip codes. Column A shows location name (irrevelant) and column B is a comma-separated list of zips. In column C+ I want only the zip codes that are a duplicate of the entire column B to be shown.

Location Name	Zip Code List	[Output]Col C	Col D	Col E
Home 1	37075,37066,37072	37075	37066	37072
Home 2	37066,37072	37066	37072
Home 3	37072,37112,37089	37072
Home 4	37075,37067	37075

In this case above, Column C, D, E are the expected output.

I currently have the following in cell C2 =filter(split(B2,","),arrayformula(countif(split(B2,","),B2)>1))

But this is not working.

Solution

SPLIT column B by , and pass the split array to COUNTIF as both range and criterion to get the count of each element in the array. IF count>1, return the array, else return nothing.

Sample:

=ARRAYFORMULA(
  LAMBDA(
    s_arr,
    IF(
      COUNTIF(s_arr,s_arr)>1,
      s_arr,
    )
  )(SPLIT(B2:B6,","))
)