I would like to know how many times I could split my hives safely, so that they have the time, and the capacity to build up successful colonies.

Some commercial beekeepers I know, and work with split (all) their hives three times every year. I thought this was too much, but it works well with them. Would this require a lot (I mean a lot) of feeding?

Also, is it bad that I feed them honey from other hives? My brother works on proccessing (extracting, bottling, distributing) honey for a very large commercial beekeeper, and they have a lot of honey which they have no use for (if it gets dirty, you know). I've talked with one beekeeper and he said I should not feed my bees this honey because it will pass on diseases to them.

Thank you,