Let me get this right you and to run coax from your radio to 3 antennas inside your house, right?, one antenna will do in some cases such as this, if you want to run three radios on three antennas, in different bands that is a different animal.
For the former situation RG8X might be sufficient but losses along the feedline vary with frequency.
Yeah, we need a much clearer picture of what you're trying to do here before we can offer any really relevant advice.
How many receivers?
How many antennae?
How many coax runs total?
What bands primarily?
All indoors, no outdoors?
Any connectors, splitters, multicouplers, relays, or anything else inline?
I ask, because it sounds like you may be trying to overcomplicate this.
Regardless, this chart will show you the performance characteristics and differences between all of the available coaxes. Of course, it is always theoretically best to choose the best coax you can afford. However, you will not always notice the difference, especially in a run of fifty feet or less. At that distance, you will hardly notice a difference between RG-58 and LMR-400 except in price and flexibility. And really, those are the two that are most commonly used in fixed station applications by scannists.