Multiple people walking me down the aisle

I have not seen anything like that, but I think it's a really lovely idea. People do walk down the aisle with two, and handing you off to another set halfway down is a really nice way to make sure they are all included. Very sweet.

The onnnnlyyyy downside I foresee, is once they've handed you to your mum and other brother, do they continue to follow you down the aisle and find their seats? do they sit in the seats halfway down the aisle that maybe your other brother and mum have just vacated, or will the second set be standing?

It would be a shame if your two older brothers ended up with the worst view of proceedings due to the logistics, if you follow me?

You could definitely do this! As Rosie mentioned, I would have a plan for the two brothers that hand you off halfway down the aisle. Perhaps they could continue to follow you down the aisle, then all of them sit in seats reserved for them in the front row.