Questions for authors with multiple publishers

Hi

Apologies in advance if this is convoluted. Here goes:
My first two books were recently offered a home by a large e-pub (Pub A) with a good reputation. I've signed and returned the contracts and am looking forward to the editing experience. My current wip is almost ready for submission and although I really like Pub A they don't publish print books. I have an e-pub (Pub B) in mind that does. Pub B, incidentally, also offered on my first book, but I decided to go for Pub A as they offered for both first and second. I know I could have gone for one book with each publisher, but I was wary of doing editing on two books simultaneously plus everything else: full-time day job, small children and part-time degree. I'm not under an option clause at Pub A, and my third book is a different sub-genre of romance to the ones they bought.

So... Would I be burning bridges if I don't submit my third book to Pub A? Should I mention to my editor that I am submitting it elsewhere? I'd love for them to publish it if Pub B decides to pass. How do you manage your submissions to other publishers without stepping on toes? I guess this is where an agent would have come in handy.

I'm planning to use a different Pen Name for the new book(s) as they're "otherworldly". I would like to continue at Pub A for future books like the two they bought from me, and Pub B (Ha! If they offer) for my off-planet books.

Any advice on how to handle this most welcome.

Undercover: No worries, both pubs accept sim subs and I'm not under a right of first refusal for either. I can be ditsy at times, but thankfully would never mention I was subbing to them because the other had rejected it! Thanks for the advice.

Torgo: What you describe is what I'm afraid of. I am a fledgling author and I really like my publisher (so far anyway as only just signed contracts. My editor seems lovely, and has taken lots of time to SKPYE. They've taken a risk on me as a newbie and have mentioned "growing me" as a writer. All great, but a part of me hankers to see my books in print, and to have the experience of another great publisher with my other sub-genre. My husband, a businessman, says Pub A would have no qualms in rejecting my new book if they deemed it unworthy so I shouldn't get cut up over subbing it at B, regardless of whether that's their main competitor. Lots to consider. Thank you very much for your input.