Can both the old(migrated from another external HD) and new time machine backup be read on iMac?

HI,

I lately migrated the time machine backup from an external HD(WB) to a new one(G Drive). If I connect the new one i.e. G Drive to my iMac for Time Machine, will there be a new folder created in G Drive? Will it be a new backup i.e. backup everything on iMac? Can the old time machine backup be read when I enter Time Machine on my iMac? Thanks in advance.