How much are we talking in the recipe?
If it's 0 to 15ml (0 to 1/2 oz), then I don't think you should go to great
depths to match the flavour. I'm thinking of the Zombie or the Mai Tai when I
mention that; apricot brandy is a bit hard to come by in these parts for the
Zombie (not that you'd notice it anyway) and Orgeat used to be a bitch to
source for me, so we do what we can. Passable-y Peach (hmm, could be a
cocktail name) flavours would be fine with a dash of sumpin-sumpin to add
depth. If it's over 15ml, or you plan on making a lot of the recipe, then you
should start investing in a small bottle of peach-flavoured brandy. ;)
Adam