technically its possible, you can use propert .htaccess setting or even DNS setting. and host 3 as different server ( either as subdomain or subfolder) such that.
coming to login there can be couple of ways, but hte easy and quick sure is this.
(1) the simplest is allow registration only via elgg, and password change also via elgg,
(2) then backport the login table to remaining two platforms login table. ( via stand alone daemon server). this you do on all three events( registration, email change password change)
coming to look , obviously they will differ, there is no doubt about it. the only way possible is to have a good designer to make them look alike as much as possible.
You would probably need to post this in the paid plugin group so developers can pick up the job.
Ok will do.
No problem, here's the link: Professional Services
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