I am opening a town home dividing wall, block, to connect two units.
Not sure to how to support wall while making opening.
Should block come out then install lintel?

"STRONG BOYS"  are what you need, see link (and any hire company will rent them and the acro props...)

http://www.strongboy.co.uk/index.php?,

cut the required slots for the strong boys above where the lintol/s will go, install strong boys and props, then remove the area of brick/block work where the lintol/s would go, and install the lintol/s.. and allow to set, then you can remove the SB's and the remaining brick/block work to give you the opening..

hope this helps