Create a new column in pandas dataframe and fill in the value based on condition in Python

Question

I have a pandas dataframe with following columns.

id                                      term                    cross_ref
https://identifiers.org/meddra:10000059 Abdominal discomfort    http://snomed.info/id/43364001
https://identifiers.org/meddra:10000060 Abdominal distension    http://snomed.info/id/162068007
https://identifiers.org/meddra:10000081 Abdominal pain          http://snomed.info/id/21522001
https://identifiers.org/meddra:10029354 Neutropenia             http://snomed.info/id/165517008
https://identifiers.org/meddra:10029366 Neutrophil count decreased  http://snomed.info/id/165517008
https://identifiers.org/meddra:10029367 Neutrophil count less http://snomed.info/id/165517008

I would like to check if the value in 'cross_ref'column is identical then pass on the value of id (from another row) to a new column.

The expected output is:

id                                      term                    cross_ref                        id2           term2         
https://identifiers.org/meddra:10000059 Abdominal discomfort    http://snomed.info/id/43364001
https://identifiers.org/meddra:10000060 Abdominal distension    http://snomed.info/id/162068007
https://identifiers.org/meddra:10000081 Abdominal pain          http://snomed.info/id/21522001
https://identifiers.org/meddra:10029354 Neutropenia             http://snomed.info/id/165517008   https://identifiers.org/meddra:10029366   Neutrophil count decreased
https://identifiers.org/meddra:10029354 Neutropenia             http://snomed.info/id/165517008 https://identifiers.org/meddra:10029367 Neutrophil count less

Any help is highly appreciated.