Crappy image, shitty sound quality, but it's just for a quick preview of what happens.
Using several modules in the patch:
Clk seq/Clk div
VC divider x2
DIY trigger combiner
DIY switch trigger combiner
The DIY switch trigger combiner is made from a doepfer switch multiple, 7 and 8 converted to ouputs for bus 1 and bus 2, both switches replaced by leds, diodes on each input.
Thanks to Gillou for the explanations and advices.