Wiktionary
lease line
n. The limit of the tenant space, either physically demarcated (by a demising partition or demising wall) or imaginary, controlled by the tenant of a leased, typically retail space, in a multi-tenant establishment, such as a mall.
Usage examples of "lease line".
Heller turned the desk speaker phone around to face him and Vantagio pushed the lease line button.
Heller apparently had a lease line to Ochokeechokee and he went into a lot of chatter about some regulation they'd come up against down there about the allowable heights of stacks in swamps.