Adding Formulas to Predecessors Column...Or Is there a Workaround?

Hi there,

Okay, so here's what I'm trying to do. Our team is using a smartsheet schedule and within that schedule, is a bunch of sub-schedules, that all work together in glorious harmony

Up until now, I've been able to use the Predecessors column with ease, for e.g. 1FS + 5d, meaning that the project on the 2nd row will start 5 days after the project on the first row ends. And each project typically used to have roughly the same amount of lag/prep time in between, so not very brain consuming. 

However, now, our predecessors have to take into account which TYPE of project is being kicked off next, which will determine how much lag/prep time there is between the end of one project and the start of the next. The type of the subsequent (next in line) project will determine the predecessor, so lets say if its a Basic project, it will be +5d...if its a Hybrid project, it will be +8 days, and if its a Complex project, it will be +11 days.

The lag time is different for each, and all of these different types of projects are sprinkled throughout the entire 170+ rows of projects. Not in a random order, but they're not all in one uniformed location. And since our schedule changes almost daily, with things moving around in all directions, it would be heartbreaking to try to manually track which types of projects moved where and update each predecessor that was affected. I can't even imagine doing that!

I've tried to add a formula to the Predecessors column, but Smartsheet won't let me.

Any suggestions/tips/comments would be widely appreciated!

Grazie.