Sistering a floor joist.

[Bouba]

How do i sister these 2 floor joist please. It seems like when houses were built,they left the floor joist short of the external wall to accomodate for the toilet pipe. I am removing this toilet pipe completely . Can i sister new floor joists in the same size by bolting and running them in outer wall like others. Thank you.
View media item 82980

 

[gregers]

could you not do a trimmer/trimming process here?

 

[Bouba]

I want to extend the joist into the external wall and remove that angled section.
The window on the pic is the external wall.

Would bolting new joist halfway from existing and sitting it on external wall be easier or trimming. I want it to be solid as above it is a toilet pan so will have weight on it.