need help identifying a set of books (Mills & Boonish type)

[ruggief]

i need to know the titles of a set of books set around a family of brothers who are either sheriffs or a fireman. the series also includes a family friend that a book is set around. The last book is about a sister they knew nothing about?? My mum is looking for these, she reads a lot of Mills & Boon,Nora Roberts etc so will be something like this, any ideas???