Can I use my own SD IRA (from 401k) and SD Roth in the same project?

[Shera Gregory]

I did try to see if this was answered already but didn't find an exact match to this question. I have a SD Roth IRA and I have the opportunity to begin a Roth 401K at work instead of my regular 401K. I plan to work another few years so it would be great to build up some $$ in a Roth 401K that I could roll into a SD plan when I retire. Question is .. at that point can I use funds from my SD Roth and my SD (former) Roth 401K into a single project? I know I can't combine funds with non-allowed entities. But what about with myself?