help with choosing correct controller

Hi There,

i am going to purchase a Pioneer DJ controller, like the DDJ-SX or DDJ-SZ i have two turntables that i want to plug into the controller, i understand this is possible as its a 4 channel mixer.

My question is, can i control Serato DJ using the controller on channel 1 and 2, and then use channel 3 and 4 to play my turntables through, so in a sense, mixing both vinyl and serato at the same time? all through one sound output source.

if you can offer some advise that would be great thank you.