As far as my understanding goes, as you're talking about some website design, you might be seeing the RGB colors (as opposed to CMYK, I mean). Hence, if you wish to create the same combinations for some other base color, the only way as I see it is by manually swapping the values constituting the R, G and B color scales (though it might not lead to very impressive results).
For example, if you're seeing a color that has a value, say
#FF7700 which has Red base followed by Green and finally Blue; if you wish to see how the color looks with a Green base, followed by Red and finally Blue, you can simply swap it as
#77FF00 which would have a Green base.
The same can be achieved in case you need to do it with the RGB color codes instead of HEX. For example,
RGB(255,119,0) would be a Red base with Green added onto it, whereas
RGB(119,255,0) would be the vice versa.