It's been a years and I don't have access to Signa, but from what I remember, there are many different ways to do it in Signa.
What you want is Scheme.
There are default schemes that will easily cover what you want but you can create custom scheme and number it however you want.
If you go with 4pg scheme, you can let it "repeat" on a sheet 4 times or create custom 4up covers scheme without repetition where you manually number it, like in Preps.
Sorry I can not be of more help, if I had Signa I would be able to help you out, but this should point you in right direction.
What you want is Scheme.
There are default schemes that will easily cover what you want but you can create custom scheme and number it however you want.
If you go with 4pg scheme, you can let it "repeat" on a sheet 4 times or create custom 4up covers scheme without repetition where you manually number it, like in Preps.
Sorry I can not be of more help, if I had Signa I would be able to help you out, but this should point you in right direction.