I have 2 girls, 7 months and 18 months, and have recently rescued a male aged 4 years, same breed.  he was bought up with another entire male and they got on brilliantly. 

He is fantastic with all the family and any human but whenever the two girls go near him he growls and yesterday barked.  I am concerned so have not left the three of them alone yet.  When out walking he doesnt even look at dogs..he just isnt interested in them at all and will concentrate on me fully.

I have managed to contact his previous owners and they are baffled by it because they say he has never shown dog aggression before.

I am getting in touch with a behaviourist but thought i would ask for opinions here first.  Do you think he is just confused and scared at moving home and will settle in with them, or is he too old now to accept living with new dogs. 

I'm sure the behaviourist will be able to assess his behaviour and answer your questions but I just thought I'd let you know that I've been through something similar when I introduced a rescue dog to my in-laws dog.  They barked at each other for the first three times they met and I was so worried that every family occasion would be fraught with tension.  Then one day the older, stronger dog just rolled over and let the younger one jump on him.  They were really good friends for the rest of their lives.

So don't despair!  Hope you (and they!) work it out.

Male dogs tend not to like puppies, and that is basically what your girls are. He may just be letting them know he isn't too happy about the change in his lifestyle, but without knowing more it's very difficult to judge. He is an adult dog, so youngsters just might not be his thing ;) How long have you had him? How do the girls behave towards him? If they are too exuberant in their welcome he could be frightened. It can take time for them all to settle down into their own little hierarchy. My male is the mediator between my  2 girls :D He lets them get on with it, up to a point, then steps in. Your dog is just settling in. Give him time :) But keep an eye on them all.

Having a good 8 dogs sometimes in my home who have been introduced from puppyhood to the elder dogs, I've found the easiest way to bond a pack is feeding time, if they all eat together it helps to cement that bond.

As long as he is not a food guarder, I would put all their bowls as close together as you can so that they are feeding next to each other.

Male dogs tend not to like puppies, and that is basically what your girls are.

This could also be a very true statement from Lindyloo, it applies to many dogs though my mum's male loves puppies young to older, so I guess it depends on the dog too. But he may be indifferent to them being older too and not wanting to play their games, if this is the reason that will change as the 18 month becomes 2, and I guess by then the 7 month will also be accepted. He may also be missing his male dog that he was brought up with. It is all a big change for him isn't it.

Feed and groom them together and hopefully he will begin to accept that they are part of his new family too well before they reach adulthood. :-)

And I agree with you not to leave them unattended until you see a bond happening.

I would agree that it could be him saying 'leave me alone, I'm confused and upset and where's my drinking buddy gone'.  The other side of the coin is that with many breeds the bitch tends to be top dog, or it would appear so and it is entirely possible that yours are giving off signals he is reading and equally he is telling them to back off because he doesn't want trouble.  Poor chap, when the girls seasons come along they will be all over him for a short time and then they will be back to tormenting him.

He is, as the others say, settling in.  The only thing I wouldn't do is feed them together.  If he is feeling unsure at this time, the girls muscling in on his food (and lets face it puppies do try it on) will IMO only serve to strengthen his insecurities.

That aside if you don't already belong to your breed club, join up now, many of them can be very helpful and certainly different breeds have different needs.

Good luck with him.