Adding a multi port valve?

I have a Hayward 1hp superpump and Perflex EC-65 D.E. filter on my 18x36 vinyl ig. It has a valve for waste at the bottom of the filter, but no multi-port valve. I have 2 skimmers plumbed onto one line, a separate wall vac line, 2 return lines - ea plumbed separately, and a main drain plumbed separately that is currently not being used. It has a minor leak and has a winter plug on it.

Is it possible to have a multiport line plumbed into my system and if so, where in the mix does it go? THX