How to add functionality such that lines for the autodetected peaks can be overlaid on each spectra

In the below code it is currently displaying the 2nd FID and showing its peak with colors as shown in attached picture. this usually generates 2 to 6 FIDs.

I want to add functionality to "Show peaks" button as shown in the figure attached of the app. Hence, it shows peaks of all the FIDs with selected colours when flickering through button "previous FID" and "Next FID" mentioned on both side of "show peaks" button.

% create index for all FID files  
str = 'fid';
    index_fid = [];
    for k = 1:numel(sTWIX)
        if any(strfind(sTWIX(k).name,str))
            index_fid = [index_fid k];
        end
    end
    N.Fid = numel(index_fid);
% Assign indice variables to app
    app.N = N;
    app.index_me_bSSFP = index_me_bSSFP;
    app.index_fid = index_fid;
    
% Process all FIDs and display 2nd FID in GUI 
    FIDs = struct;
    for k = 1:numel(index_fid)
        [FIDs(k).frequency, FIDs(k).spectrum] = FID_process_app(sTWIX(index_fid(k)), ...
            sTWIX(index_fid(k)).files);
    end

% Store FIDs in app
    app.FIDs = FIDs;

% Auto detect peaks
    for t = 1:length(FIDs)
    FID_spec_max(t) = max(FIDs(t).spectrum); % See max signal from each spectra
    end
    
    [Pyr_sig spec_pos] = max(FID_spec_max); % Identify max signal from all spectra
    
    temp_spec = FIDs(spec_pos).spectrum;
    
% Locate pyruvate position
    [Pyr_sig Pyr_spec_pos] = max(temp_spec); % Locate pyruvate signal position
    pyr_freq = FIDs(spec_pos).frequency(Pyr_spec_pos) % Identify pyruvate resonance frequency

% Locate urea position
    Ure_sig = max(FIDs(spec_pos).spectrum(Pyr_spec_pos-150:Pyr_spec_pos-90));   
    Ure_spec_pos = find(abs(FIDs(spec_pos).spectrum) == abs(Ure_sig));    
    ure_freq = FIDs(spec_pos).frequency(Ure_spec_pos) % Identify urea resonance frequency
    
% Locate lactate position
    Lac_sig = max(FIDs(spec_pos).spectrum(Pyr_spec_pos+175:Pyr_spec_pos+225));    
    Lac_spec_pos = find(abs(FIDs(spec_pos).spectrum) == abs(Lac_sig));    
    lac_freq = FIDs(spec_pos).frequency(Lac_spec_pos) % Identify lactate resonance frequency

% Locate hydrate position
    Hyd_sig = max(FIDs(spec_pos).spectrum(Pyr_spec_pos+120:Pyr_spec_pos+150));   
    Hyd_spec_pos = find(abs(FIDs(spec_pos).spectrum) == abs(Hyd_sig));    
    hyd_freq = FIDs(spec_pos).frequency(Hyd_spec_pos) % Identify hydrate resonance frequency
    
% Locate alanine position
    Ala_sig = max(FIDs(spec_pos).spectrum(Pyr_spec_pos+80:Pyr_spec_pos+110));    
    Ala_spec_pos = find(abs(FIDs(spec_pos).spectrum) == abs(Ala_sig));    
    ala_freq = FIDs(spec_pos).frequency(Ala_spec_pos) % Identify alanine resonance frequency

% Load auto detected values in    
    app.F1EditField.Value = lac_freq;
    app.F2EditField.Value = hyd_freq;
    app.F3EditField.Value = ala_freq;    
    app.F4EditField.Value = pyr_freq;    
    app.F5EditField.Value = ure_freq;
    
% Plot max signal FID in GUI Axes
    plot(app.UIAxes,FIDs(spec_pos).frequency,FIDs(spec_pos).spectrum,...
        'k',"LineWidth",3.0)
    title(app.UIAxes,sprintf('Nonlocalised Spec - No. %01d',app.fid_int))
    
        % plot prediected positions
        xline(app.UIAxes,lac_freq,'r--',"LineWidth",3.0); 
        xline(app.UIAxes,hyd_freq,'b--',"LineWidth",3.0);
        xline(app.UIAxes,ala_freq,'g--',"LineWidth",3.0);
        xline(app.UIAxes,pyr_freq,'m--',"LineWidth",3.0);
        xline(app.UIAxes,ure_freq,'c--',"LineWidth",3.0);