Complex sentence: The Grateful Dead similarly performed several Coasters songs in their early days; they were influenced by a weekend in 1965 in which the Dead (while still called The Warlocks) served as pickup band for the Coasters at a lounge in Belmont, CA.
Split into simpler sentences: The Grateful Dead similarly performed several Coasters songs in their early days. This was influenced by a weekend in 1965 in which the group (while still called The Warlocks) served as pickup band for the Coasters at a lounge in Belmont, CA.