Need to remove all but 5 newest files, matching name, leave all files that don't match.

Using examples from other sources, I have the following script.  It finds the five newest files in Arguement1, matching an string from Arguement2, and deletes the rest. 

$Zpath = $args[0]
##write-host $Zpath

$Zfile = $args[1]
##write-host $Zfile

# Get all the items in Zpath
Get-ChildItem -Path $Zpath |

# Skip directories
Where-Object { -not $_.PsIsContainer } |

# Only get files that match certain format
Where-Object { $_.Name -match $Zfile } |

# Sort them by name, from most recent to oldest
Sort-Object -Descending -Property CreationTime  |

# Keep the first five items
Select-Object -Skip 5 |

Remove-Item #-WhatIf

The problem is some folders are storing mutliple files in the same folder.  
For Example, in the folder we have:
Eggs_20191101
Eggs_20191102
Eggs_20191103
Eggs_20191104
Eggs_20191105
Eggs_20191106
Eggs_20191107
Bacon_20191101
Bacon_20191102
Bacon_20191103
Bacon_20191104
Bacon_20191105
Bacon_20191106
Bacon_20191107
Bacon_20191108
Bacon_20191109

If $Zfile is Eggs, I want to delete all but the five newest Egg files and leave all the Bacon files alone.

-Al H