Q:

Chartwell fonts and changing colour with ligatures

Bit of a niche question. There is a beautiful set of TrueType fonts called Chartwell designed for producing graphs from text.
I am trying to get these to work in Latex.
I have switched to Xe(La)tex, and can now get the fonts to appear.
However I would like to change text colour without sequence of numbers being split into two.
Best explained with some code and a picture.
\documentclass[13pt]{article}
\usepackage{fontspec}
\usepackage{xcolor}

% Now define your quick commands for switching fonts
\setmainfont{ChartwellRose}
\newfontfamily\cwrose[Ligatures=Rare, Color=blue]{ChartwellRose}

\begin{document}
\raggedright

Here is the text without ligatures

\fontsize{48}{60}
\selectfont
40+20+50
\rmfamily
\normalsize

Here is the text with ligatures

\cwrose
\fontsize{48}{60}
\selectfont
40+70
\rmfamily
\normalsize

Here is the text with a colour change inserted

\cwrose
\fontsize{48}{60}
\selectfont
40+\addfontfeature{Color=red}+70
\rmfamily
\normalsize

And as you can see the colour change has broken the effect of enabling the ligatures and the 'rose' is now presented as two separate objects (rather than a single object with 2 different colours.

\end{document}

Is it possible therefore to change the colour of a part of the text without the ligature formation being broken?
Here is a screenshot of the compiled example and here is a screenshot of unbroken form of the last example

A:

I can confirm that FF Chartwell works as intended using the luacolor package.
Edit:
As requested by Stephan here is a MWE. This is for luatex only (so this is a workaround rather than a complete answer to the question by drstevok). 
\documentclass{article}

%Fontspec
\usepackage{fontspec}

%CHARTWELL (Be sure to load style set 1, otherwise the ligatures won't be activated.)
\newfontface\cwp[StylisticSet={1}]{ChartwellPies}
\newfontface\cwr[StylisticSet={1}]{ChartwellRose}
\newfontface\cwb[StylisticSet={1}]{ChartwellBars}
\newfontface\cwbv[StylisticSet={1}]{ChartwellBarsVertical}
%etc.

%COLORS (Works exactly the same as the regular latex color package.}
\usepackage{luacolor}
\definecolor{aut1}{RGB}{255,51,0}
\definecolor{aut2}{RGB}{255,102,0}
\definecolor{aut3}{RGB}{255,153,0}
\definecolor{aut4}{RGB}{255,204,0}
\definecolor{white}{RGB}{255,255,255}

\begin{document}

\begin{figure}
\centering
\fontsize{100}{120}
\cwp \textcolor{aut1}{24}+\textcolor{aut2}{31}+\textcolor{aut3}{40}+\textcolor{aut4}{5}+\textcolor{white}{A}\\
\end{figure}

\begin{figure}
\centering
\fontsize{100}{120}
\cwr\textcolor{aut1}{14}+\textcolor{aut2}{30}+\textcolor{aut3}{12}+\textcolor{aut4}{44}+\textcolor{white}{A}\\
\end{figure}

\begin{figure}
\centering
\fontsize{100}{120}
\cwb \textcolor{red}{50}+\textcolor{blue}{31}+\textcolor{green}{19}\textcolor{aut4}{=}\\
\end{figure}

\begin{figure}
\centering
\fontsize{100}{120}
\cwbv \textcolor{red}{50}+\textcolor{blue}{31}+\textcolor{green}{19}\\
\end{figure}

\end{document}

A:

This can’t be done in XeTeX, color will always break text flow and hence the ligatures, and \addfontfeature just defines a new font from the current one plus the requested features, and inter-font ligatures will not work of course. It might be possible with LuaTeX though when using the luacolor package.

