Is it possible to access piped variables without forkJoin or combineLatest?

Question

Is it possible to access previous pipe variables in RxJs appliances where forkJoin() or combineLatest() cannot be used, in my case due to value accumulation, without nesting pipes?

Or is a nested pipe with switchMap() in the following scenario even fine?

// this.incrementNavigation$ emits always 1
// this.decrementNavigation$ emits always -1

this.searchSuggestions$.pipe(
  // Can't use combineLatest() due to accumulation happening in scan()
  switchMap(search => {
    return merge(this.incrementNavigation$, this.decrementNavigation$).pipe( // Nesting begins...
      startWith(0),
      scan((acc: number, cur: number) => {
        if (acc+cur < 0) return search.length-1 // Need access to search variable
        if (acc+cur > search.length-1) return 0
        return acc+cur
      }),
    )
  })
).subscribe(pos => {
  this.searchNavigationPosition = pos
})