Using a Saved Search as criteria for a new saved search

I am trying to automate membership assignment using saved searches because membership function does not account for cumulative one-time donations reaching a designated threshold (threshold $500, I gave $300 in January and $200 in April - as of April donation I’m a member).  I’m using Activist codes at moment because Membership looks very complicated to get right.

I can add a “membership” activist code - beautifully with a “membership’ saved search as input to a bulk apply.  Now I want to remove the activist code for someone who no longer fits the criteria in my “membership” saved search.  In my mind, the easiest way is to create a new search step 1 everyone with the “membership activist code”, step 2 remove people who who are in “membership saved search”.  I see I can use a Saved List as criteria but not a search.  I’d prefer not to have to recreate the “membership search” in the “remove membership saved search”.

Any ideas?  If Membership function is not as scary as I think, any advice? Thanks