Assuming there isn't a template that would display both, don't have any registers so just asking.
One option is TileMaster, great app that can combine multiple attributes into one dashboard tile.
Alternatively, you can overlay two tiles on the dashboard and use some creative CSS coding to give it the desired look. You situation might be a little more complicated but an example, I have Halo Smoke Detectors that can be displayed as smoke or CO detectors using the built-in templates. Below is two tiles, overlayed to be the size of one. Smoke on left/CO on the right

CSS
/*Left*/
#tile-7 .tile-primary {
display:block;
position:relative;
width:50%;
top:33%;
}
/*Right*/
#tile-8 {
border-left:none;
background:transparent !important
}
#tile-8 .tile-primary {
display:block;
position:relative;
left:33%;
top:33%
}
#tile-8 .tile-title {
display:none;
}