I do not think you could stop somebody from forwarding on an invite.
You could insert a signature/disclaimer stating that the invitation is intended for the person the invite was sent to, and if it were passed on the invite is void.
Alienware 17 R4 2017 review
These brilliant Lego posters show just what children's imaginations are capable of
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Comment réinitialiser votre PC, ordinateur portable ou tablette Windows ?