Cloudformation : Associate PublicIP to EC2 instance among multiple network interfaces with EIPs

Question

My Setup :

• Three Network Interfaces
• Two EIPs attached to two network interfaces
• Associating both the EIP to the instance using network interface

I am using cloudformation and code snippet for this is below

  vSRXEip11:
    Type: 'AWS::EC2::EIP'
    Properties:
      Domain: vpc
      Tags:
        - Key: Name
          Value: ManagementElasticIP
  vSRXEip12:
    Type: 'AWS::EC2::EIP'
    Properties:
      Domain: vpc
      Tags:
        - Key: Name
          Value: RevenueDataElasticIP
  AssociateEIP11:
    Type: 'AWS::EC2::EIPAssociation'
    Properties:
      AllocationId: !GetAtt
        - vSRXEip11
        - AllocationId
      NetworkInterfaceId: !Ref vSRXInterface11
  AssociateEIP12:
    Type: 'AWS::EC2::EIPAssociation'
    Properties:
      AllocationId: !GetAtt
        - vSRXEip12
        - AllocationId
      NetworkInterfaceId: !Ref vSRXInterface12
  VpcvSRXEC2Instance1:
    Type: 'AWS::EC2::Instance'
    Metadata:
      Comment1: Launch Juniper VSRX1
    Properties:
      InstanceType: !FindInMap
        - vSRXInstance
        - !Ref VSRXType
        - Type
      KeyName: !Ref KeyName
      DisableApiTermination: !If
        - EnableTerm
        - true
        - false
      ImageId: !FindInMap
        - JunipervSRXAMI
        - !Ref 'AWS::Region'
        - byol
#https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-ec2-network-iface-embedded.html
      NetworkInterfaces:
        - NetworkInterfaceId: !Ref vSRXInterface11
          DeviceIndex: '0'
        - NetworkInterfaceId: !Ref vSRXInterface12
          DeviceIndex: '1'
        - NetworkInterfaceId: !Ref vSRXInterface13
          DeviceIndex: '2'
      Tags:
        - Key: Name
          Value: Juniper VSRX1
    DependsOn: IGW

When I deploy above cloudformation template, I see sometimes vSRXEip11 attached as public IP and sometimes vSRXEip12.

How should I make the public IP address of EC2 instance to either vSRXEip11 or vSRXEip12 ?

I tried with associatePublicIPAddress for one of the network interface like below.

  VpcvSRXEC2Instance1:
    Type: 'AWS::EC2::Instance'
    Metadata:
      Comment1: Launch Juniper VSRX1
    Properties:
      InstanceType: !FindInMap
        - vSRXInstance
        - !Ref VSRXType
        - Type
      KeyName: !Ref KeyName
      DisableApiTermination: !If
        - EnableTerm
        - true
        - false
      ImageId: !FindInMap
        - JunipervSRXAMI
        - !Ref 'AWS::Region'
        - byol
#https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-ec2-network-iface-embedded.html
      NetworkInterfaces:
        - NetworkInterfaceId: !Ref vSRXInterface11
          DeviceIndex: '0'
          AssociatePublicIPAddress: true
        - NetworkInterfaceId: !Ref vSRXInterface12
          DeviceIndex: '1'
        - NetworkInterfaceId: !Ref vSRXInterface13
          DeviceIndex: '2'

But got an error saying "The associatePublicIPAddress parameter cannot be specified when launching with multiple network interfaces"