No — each tenant needs their own application. A single application cannot cover more than one tenant.
On a joint tenancy, every tenant who needs guarantor cover applies to The Student Guarantor separately for their own share of the rent, and each approved tenant gets their own guarantee.
The same co-signer can support more than one applicant. A parent guaranteeing two siblings, for example, can act as co-signer on both — but each tenant still submits their own application, and each application needs its own co-signer invitation.
Your Guarantor Service Fee is based on your own share of the rent, so two tenants in the same property can be quoted different amounts.