Can books from one series be tied to another?

     I couldn't resist the title! You know I love tying things up! Reader's have written about how much they'd like to see more of Colt and Alexis from Master's Email which got me creating several scenarios. What if...Colt and Alexis were invited to one of the bondage parties that Nick and Sondra attend from The Boss's Pet series? Well let me tell you! OMG! My mind went crazy with all kinds