I came across this piece of code, while trying to find a solution. It doesn't do exactly what you want, but it should be ez to add extra branch names on the if statement.
Works for me, so far. it forces pull --rebase for the same branch and lets regular merges with other branches go through.
All credits go to the original author.
#!/bin/bash
#
# This git update hook will refuse unnecessary merge commits caused by pulling
# from being pushed to a shared repository. These commits make following the
# history of a project difficult and are always avoidable with rebasing.
#
# by Scott Kyle (appden)
# modified by Olivier Refalo (orefalo)
refname="$1"
oldrev="$2"
newrev="$3"
# if this is not run as a hook, you may have messed up
if [ -z "$GIT_DIR" -o -z "$refname" -o -z "$oldrev" -o -z "$newrev" ]; then
echo "Usage: GIT_DIR=<path> $0 <ref> <oldrev> <newrev>" >&2
exit 1
fi
# if the new revision is all 0's then it's a commit to delete a ref
zero="0000000000000000000000000000000000000000"
# also check if the new revision is not a commit or is not a fast forward
# detect branch deletion, branch creation... and more
if [ "${refname#refs/heads/}" = "master" ] || [ "$newrev" = "$zero" ] || [ "$oldrev" = "$zero" ] || [ $(git cat-file -t $newrev) != "co
mmit" ] || [ $(git merge-base $oldrev $newrev) != "$oldrev" ]; then
exit 0
fi
# loop through merges in the push only following first parents
for merge in $(git rev-list --first-parent --merges $oldrev..$newrev --); do
# lazily create the revision list of this branch prior to the push
[ -z "$revlist" ] && revlist=$(git rev-list $oldrev)
# check if the second parent of the merge is already in this branch
if grep -q $(git rev-parse $merge^2) <<< "$revlist"; then
cat >&2 <<-EOF
*** PUSH REJECTED ***
*** TRIVIAL merge detected on local branch ${refname#refs/heads/}
*** To fix: git rebase origin/${refname#refs/heads/}
***
*** Next time use: git pull --rebase
***
*** Permanent fix: git config [--global] branch.autosetuprebase always
*** Then for existing branches: git config branch.<name>.rebase true
EOF
exit 1
fi
done
echo -Info- Clean history successfully preserved!
exit 0