Fuel lines

One more stupid question. Lol with the return line. Once I get it back to the tank at the top inlet can I put a T in it right there and run my vent like I posted before? So the return and vent would be in the same line or would that cause problems?
I would think you would want something like a PCV kind of valve or a check valve in the vent hose so it doesn't push feel up at but can take are in as the tank gets lower...