Is it possible to communicate single SPI slave with Two SPI masters
As others have already said in the comments to your question - you can't simultaneously have 2 masters on an SPI bus. It just doesn't work that way.
But the setup you describe (ignoring your master/slave terminology) could work.
Only your Master-1 stays being a master. Your existing Slave stays as a slave, and your Master-2 becomes a slave, but you connect its data lines as if it's a master.
So:  







simulate this circuit &ndash; Schematic created using CircuitLab

Your Master-1 will Chip-Select both Slave-1 &amp; New-Slave-2(Old-Master-2) at the same time, and then when Slave-1 sends data out on its MISO, this data will be received by Master-1 on its MISO (as expected), and also by New-Slave-2 on its MOSI.