check if a SSM parameter is available resolve it else leave it blank in a policy in cloud formation template

Question

I am creating ssm parameter in a different stack that stores a kms key , Now I want to use this ssm parameter to be resolved in a different stack if it is available else leave it empty.

Stack 1:

  KmsKeySSM:
    Type: AWS::SSM::Parameter
    Condition: EnableTrans
    Properties:
      Description: ETL Glue Job Security Config Kms Key
      Name: !Sub '/app/glue/etljob/${ProcessType}/${ApplicationName}/kmskey'
      Type: String
      Value: !GetAtt GlueJobKmsKey.Arn

Stack 2:

  AWSGlueJobRole:
    Type: "AWS::IAM::Role"
    Properties:
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Principal:
              Service:
                - glue.amazonaws.com
            Action:
              - sts:AssumeRole
      ManagedPolicyArns:
        - arn:aws:iam::aws:policy/service-role/AWSGlueServiceRole
        - arn:aws:iam::aws:policy/AWSLakeFormationDataAdmin
      Policies:
        - PolicyName: !Sub app-dih-iceberg-kmspolicy-gluecatalog-${ApplicationName}
          PolicyDocument:
            Version: 2012-10-17
            Statement:
              - Effect: Allow
                Action:
                  - "kms:DescribeKey*"
                  - "kms:Encrypt*"
                  - "kms:Decrypt*"
                  - "kms:ReEncrypt*"
                  - "kms:GenerateDataKey*"
                  - "kms:GenerateDataKeyWithoutPlaintext"
                Resource:
                  - !Sub '{{resolve:ssm:/app/dev/glue-catalog/kms}}'
                  - !Sub '{{resolve:ssm:/app/dev/central-catalog/glue/kms}}'
                  - !If [!Sub '{{resolve:ssm://app/glue/etljob/trans/${ApplicationName}/kmskey']

here in resource I want to check if the stack 1 SSM parameter exists else leave it empty or dont use it like this I have two ssm parameters that I want to refer conditionally

I dont want to use an extra parameter in this case.