Italian record label Frontiers has somehow become a natural home for persistent hard-rock and hair-metal bands, from Survivor and Boston to Pretty Boy Floyd and Lynch Mob, looking to internationally release new albums in this brave new streaming world. Four of the label’s artists — L.A. Guns, Warrant, Jack Russell’s Great White and Riverdogs (featuring Vivian Campbell of Def Leppard) — will combine their powers like a heavy-riffing Voltron for this Frontiers mini-festival, tagged “A Rockin’ Christmas Bash.” So what if L.A. Guns and Russell’s version of Great White have only about three original members between them? This is party music being performed by seasoned pros. Between these bands, there will be enough ’80s anthems over the course of the evening to keep host Eddie Trunk happy until Easter.