You can use below grok for splitting (http-WEB0001VR%2F10.351.100.19-1000-15)
(?[a-z]+-[a-zA-Z0-9]+%[a-zA-Z0-9]+.[0-9]+.[0-9]+.[0-9]+)-(?[0-9]+)-(?[0-9]+)
{
"Server": [
[
"http-WEB0001VR%2F10.351.100.19"
]
],
"port": [
[
"1000"
]
],
"Response id": [
[
"15"
]
]
}