@vivek11 

you can use field level WRITE ACL

Something like this, add for both the fields

answer = gs.getUser().isMemberOf('Group ABC');

OR

You can use Display business rule and onLoad client script

Display Business rule:

(function executeRule(current, previous /*null when async*/ ) {
    if (current.state.toString() == '-1' && gs.getUser().isMemberOf('Group ABC')) {
        g_scratchpad.canEdit = 'true';
    } else {
        g_scratchpad.canEdit = 'false';
    }
})(current, previous);

onLoad client script:

function onLoad() {
    // Check the g_scratchpad variable set by the Display Business Rule
    if (g_scratchpad.canEdit == 'false') {
        // Make the Description and Short Description fields read-only
        g_form.setReadOnly('description', true);
        g_form.setReadOnly('short_description', true);
    }
}

If my response helped please mark it correct and close the thread so that it benefits future readers.