As you've not had a reply as yet perhaps this may help by letting you contact the hotel direct.
P.O. 175, Cala Llonga - 07840 - Santa. Eulalia
Tfno: 971 196 471 - Fax: 971 196 491
E-mail: imperial@sirenishotels.com

I know that when I stayed there before that part of the Imperial hotel was hived of into the Serinis Club Playa guest could use either the Imperial or the Dorada except for their meals but that was many years ago. It may not be the same as the Club is All Inclusive.