Combine stack into hyperstack

[mmettlen]

I have 3 stacks (raw image time series, deconvolved time series and an 'overlay time series') that are all three in RGB. I'd like to combine them into one Hyperstack where each individual stack is treated as a separate slice (z) - I assume that treatment as a separate channel (c) doesn't work as the stacks are in RGB...
How can this be done?