I'm sure I've asked this before but I can't find it now.

I'll be arriving at T3 from YEG (Westjet) and then departing from T3 again 4 hours later on Westjet to LGW (UK).
There are no Priority Pass restaurants at all in T3, all three of them are in T1. There are no PP lounges at all anywhere in YYZ.

Question: can I go from T3 to T1 (to get at those restuarants) without passing through security again? After googling, I suspect the answer is NO but what a hassle if someone is connecting there domestically.
I've tried in the past to get into T1 with a T3 boarding pass and was refused, no surprise there.