Hey Todd,
I’ve been running into the same problem when i overlay lower 3rds on my video track. I’m no scientist, but it seems to me that there is no quick way of adding default transitions to multiple video tracks. I’ve tried a few things and that function only works if you are adding transitions to multiple clips on the same track. That being said, if you find out a good shortcut please let me know, i edit everyday using lower thirds and it’s a pain in the ass having to put in two transitions for every graphic. If i find anything out i’ll post it here.
Good Luck