Sorry, no. If you're staying at any All-Star, you can use the other pools at the other All-Star resorts. But if you're staying at Pop, you can only use the pools at Pop.
The good news is, there are 3 pools at Pop. All are themed differently. There's really no significant difference between the Pop pools and the All-Star pools, none of them have slides or anything like that, so there's no advantage to using the All-Star pools anyway. It'd be the same sort of pools, just different theming.