The Gigrig has 1 midi out right. Does it generate a clock (click), if it doesn't generate a clock, the cheapest easiest way to achieve what you want is to insert a device before the eventtides that does, like the tempode. If the Gigrig does, then just have the Gigrig set the tempo and set the out on the first device to thru.
Otherwise you will could get a merger/splitter combo in order to pass program change and clock to the second unit, sadly you only have the choice of out or thru on the eventide units.
You can research some stuff here: http://www.midisolutions.com/products.htm all this stuff can be mounted under your board…
