Need help creating a semi complex macro

I am attempting to create a macro that presses multiple buttons, waits for a specific delay that may be different for each keypress, then repeats as long as the toggle is active. I intend to use this macro to allow me to press a button on my mouse, which will toggle automatic usage of flasks in Path of Exile, and then refresh those flasks whenever the effect expires until I press the mouse button again to disable the toggle.

So far, I have been successful at creating a macro that will press the relevant buttons then create a delay before repeating continuously. I did so by inserting a keypress for all relevant keys, then inserting a blank key release with a delay added to it, then checking the toggle continuous playback option when binding the macro to my mouse button. This works so long as the flasks I intend to use all have the same effect duration, but it will not work when the duration is different, as every delay that I add through any method I've tried performs the delays sequentially rather than simultaneously. I've tried creating multiple macros with their own separate delays and adding them as macro groups into a single macro, but again, it will then perform each macro with their individual delays sequentially, which is not what I need.

Is there a way to force delays to occur simultaneously? I do 'not' want to simulate simultaneous delay by calculating the difference between the delays and continuing a large loop of commands until the total delay is equally divisible by all individual delays, as that would be an excessive amount of editing every time I change flasks to one with a different effect duration. Is there a way to accomplish simultaneous delay progression in a macro, or any other method that would suffice for this purpose? If there is, how would I go about implementing it? Thanks in advance for any help in this matter.