How to add aliases to sitemap.xml?

Hi!

I have this custom sitemap to hide some pages from sitemap like form-success page, and would like add the aliases of some pages to sitemap.xml
Is this possible?

{{ printf "<?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"yes\"?>" | safeHTML }}
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
  xmlns:xhtml="http://www.w3.org/1999/xhtml">
  {{ range where .Data.Pages "Params.sitemap_exclude" "ne" true }}
    {{- if .Permalink -}}
  <url>
    <loc>{{ .Permalink }}</loc>{{ if not .Lastmod.IsZero }}
    <lastmod>{{ safeHTML ( .Lastmod.Format "2006-01-02T15:04:05-07:00" ) }}</lastmod>{{ end }}{{ with .Sitemap.ChangeFreq }}
    <changefreq>{{ . }}</changefreq>{{ end }}{{ if ge .Sitemap.Priority 0.0 }}
    <priority>{{ .Sitemap.Priority }}</priority>{{ end }}{{ if .IsTranslated }}{{ range .Translations }}
    <xhtml:link
                rel="alternate"
                hreflang="{{ .Language.LanguageCode }}"
                href="{{ .Permalink }}"
                />{{ end }}
    <xhtml:link
                rel="alternate"
                hreflang="{{ .Language.LanguageCode }}"
                href="{{ .Permalink }}"
                />{{ end }}
  </url>
    {{- end -}}
  {{ end }}
</urlset>

Since an alias is a redirect, should it really be in sitemap.xml from the search engine’s point of view? I suspect that would lose you ranking for engines like Google.

Hi @cshoredaniel thanks for reply.
This is a new domain, new site. I’m asking about sitemap.xml not about google rank etc. I removed my custom sitemap.xml as metioned before, and aliases don’t appears on sitemap.