I don't think there is a way to share history amongst TerminalTabs only, but here something that could help you.
The history is not something handle by your terminal but by your shell (bash, tcsh, zsh...)
here some options that'll help you setup a shared history amongst all the terminal windows (the shell instances).
this should be put somewhere in your
export HISTCONTROL=ignoredups:erasedups # no duplicate entries
export HISTSIZE=100000 # big big history
export HISTFILESIZE=100000 # big big history
shopt -s histappend # append to history, don't overwrite it
# Save and reload the history after each command finishes
export PROMPT_COMMAND="history -a; history -c; history -r; $PROMPT_COMMAND"