Remove rolls from packages. (Do not separate rolls.) Cut rolls in half horizontally, creating 1 top and 1 bottom per package. Spread preserves on cut sides of top of rolls; sprinkle with pecans. Spread mustard-mayonnaise blend on cut sides of bottom of rolls; top with roast beef and cheese. Sprinkle with salt and pepper, if desired. Cover with top halves of rolls, preserves sides down, and wrap in aluminum foil.