Bolting joists together

Here's a partial plan of my ground floor, with 1st floor joists supporting the floor as shown. (Yes, there are other joists - I've only drawn the relevant ones).



I want to have the diagonal wall taken down, and replaced with one at 90° like so:



Clearly this leaves a joist flapping around with no support for about 1.3m, and I can't help feeling that this is a Bad Thing.

I can think of a couple of ways to resolve this, but I was wondering if simply bolting through the overlapping section would work?

Joists are 165x50mm, or 6½x2" in old money, on approx 330mm centres.

As the overlaps are near the ends of the joists, the bending moment will be low and so fixing them together would be OK. However, contrary to
how it might seem, it would be better to use coach screws (with pilot holes of course) rather than bolts. The problem with bolts in timber is that you
get joint slip due to having to pre-drill holes fractionally larger than the bolts themselves.

For what it's worth, which is little because I am a complete rookie, I recently fixed some joists together. I glued (gorilla glue) and clamped them, then waited, then whilst clamped drilled and put through m10 coach bolts (one high then one low then one high if you get me) and then drove in a few 8mm x 70mm coach screws. It felt very very sturdy.