The transition function of a DFA is typically defined as mapping a DFA state and one input symbol to another DFA state, take Wikipedia's formal definition as an example:
A deterministic finite automaton M is a 5-tuple, (Q, Σ, δ, q0, F), consisting of
- a finite set of states (Q)
- a finite set of input symbols called the alphabet (Σ)
- a transition function (δ : Q × Σ → Q)
- a start state (q0 ∈ Q)
- a set of accept states (F ⊆ Q)
So with the usual definition of a DFA, you cannot have transitions over a sequence of two elements of the alphabet. A common kind of automaton that allows more complex transitions are Generalized nondeterministic finite automata.